STATE r  HOOU 


STATE  NORKALSCHOOL 


EXAMINATION   OF  WATER. 


LEFFMANN. 


BY   THE    SAME   AUTHOR. 


ANALYSIS 

OF 

MILK  AND  MILK  PRODUCTS. 

I2mo.    92  pages.     Illustrated.     $1.25. 


A  COMPEND  OF  CHEMISTRY, 

INCLUDING  URINARY  ANALYSIS. 

ESPECIALLY   ADAPTED  TO  STUDENTS   IN    MEDICINE 
AND   DENTISTRY. 

Fourth  Edition.    Revised. 
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SANITARY  RELATIONS 

OF   THE 

COAL-TAR    COLORS 

BY   THEODORE   WEYL. 

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I2mo.    154  pages.    $1.25. 


P.   BLAKISTON,  SON  &  CO.,  PHILADELPHIA. 


EXAMINATION  OF  WATER 


SANITARY  AND  TECHN1C  PURPOSES. 


BY 

HENRY  LEFFMANN,  A.M.,  M.D.,  PH.D., 

PROFESSOR   OF  CHEMISTRY  IN  THE  WOMAN'S   MEDICAL  COLLEGE   OF  PENNSYLVANIA, 

FREE   INSTITUTE   OF   SCIENCE;     PATHOLOGICAL  CHEMIST  TO  THE 

JEFFERSON  MEDICAL  COLLEGE  HOSPITAL;    CHEMIST  TO 

DAIRY   AND    FOOD    COMMISSIONER    OF   PA. 


THIRD  EDITION,  REVISED  AND  ENLARGED,  WITH 
ILLUSTRATIONS. 


PHILADELPHIA: 
P.    BLAKISTON,    SON    &    CO 

I  O  I  2    WALNUT    STREET. 
I895. 


Copyright,  1895,  by  P.  BLAKISTON,  SON  &  Co. 


14-2- 


I    DEDICATE  THIS  BOOK   TO   THE 
MEMORY   OF 

MY    MOTHER, 

TO  WHOSE  WISE   PRECEPT  AND   EXAMPLE 

IN    MY    BABYHOOD 

I   OWE  WHATEVER   MERIT  MY   MANHOOD  YEARS 
MAY   SHOW. 


PREFACE  TO  THIRD  EDITION. 


In  the  present  edition  the  general  character  of  the  work 
as  heretofore  exhibited  has  been  preserved,  but  numerous 
modifications  of  the  details  of  processes  of  sanitary  analy- 
sis as  developed  by  various  American  workers  have  been 
described.  Much  valuable  matter  has  of  late  years  been 
contributed  by  the  various  State  stations  for  sanitary  con- 
trol, and  while  these  methods  have  not  solved  the  difficult 
problem  presented  to  the  sanitary  chemist,  namely,  the 
absolute  judgment  as  to  whether  a  given  water-sample  is  or 
is  not  wholesome,  they  have  aided  in  securing  uniformity  of 
results,  and  the  accumulation  of  data  upon  which  judgment 
may  be  formed.  Much  of  the  text  in  the  section  on  bio- 
logic examinations  has  been  re-written,  and  I  have  taken 
occasion  to  express  more  at  length  the  sources  of  un- 
certainty in  this  field ;  sources  which  were  recognized 
and  pointed  out  in  both  the  earlier  editions,  but  which 
have  become  much  more  appreciable  to  the  profession  at 
large  within  the  last  few  years.  Whatever  may  be  the 
shortcomings  of  the  standard  analytic  examinations,  it 
seems  probable  that  for  some  years  to  come,  at  least, 
the  results  will  remain  the  most  satisfactory  basis  for 
judgment  as  to  the  potability  of  a  water.  There  can  be  no 
question  that  many  of  the  published  results  as  to  bacterio- 
logic  examinations  of  water-samples  are  without  value, 
vii 


Vlil  PREFACE   TO   THIRD    EDITION. 

partly  from  the  inherent  difficulties  of  the  methods,  even 
in  the  most  expert  and  honest  hands ;  partly,  it  is  to  be 
regretted,  from  absolute  misstatement.  I  have  had  per- 
sonal knowledge  of  one  instance  of  the  latter  phase. 

My  former  colleague,  Dr.  William  Beam,  now  perma- 
nently residing  in  a  distant  part  of  the  world,  has  asked 
to  be  relieved  from  his  share  in  the  work.  The  copy- 
right privileges  have  been  formally  transferred  to  me, 
and  I  have  conducted  entirely  the  work  of  the  present 
revision.  H.  L. 

7/j  Walnut  St. 

Philadelphia,  August  1895. 


PREFACE  TO  SECOND  EDITION. 


In  the  period  that  has  elapsed  since  the  publication  of 
the  first  edition  of  this  work,  many  processes  for  water 
analysis  have  been  proposed,  and  we  have  included  in  the 
present  revision  such  of  these  as  seem  to  us  of  substantial 
value.  In  particular  we  may  mention  the  methods  recom- 
mended by  the  Chemical  Section  of  the  American  Associa- 
tion for  the  Advancement  of  Science,  and  the  application 
of  the  Kjeldahl  process  to  the  determination  of  the  organic 
nitrogen.  The  adoption  of  the  former  methods  will  serve 
to  secure  uniformity  in  analytical  data,  while  it  is  to  be 
hoped  that  chemists  generally  will  investigate  and  report 
on  the  latter,  in  order  that  a  basis  for  the  interpretation  of 
results  may  be  obtained. 

No  material  change  has  been  made  in  the  description  of 
the  general  Quantitative  Analysis,  in  which  we  have  fol- 
lowed to  a  large  extent  the  methods  indicated  by  Fresenius, 
selecting  those  best  adapted  to  technical  purposes. 

We  have  extended  considerably  the  section  on  the 
Biological  Examinations,  although  we  have  seen  no  reason 
to  change  the  opinions  expressed  in  the  former  edition  as 
to  the  value  of  these  results.  It  would  be  impossible  to 
overestimate  the  importance  of  bacteriology,  in  etiology, 
pathology,  and  general  biology,  but  until  pathogenic  mi- 
crobes are  more  clearly  indicated  and  described,  the 
ix 


X  PREFACE   TO   SECOND    EDITION. 

methods  will  be  of  little  use  in  dealing  with  the  problem 
of  the  determination  of  the  sanitary  and  technical  value 
of  water  supplies. 

In  the  chapter  on  the  Purification  of  Water  we  have 
described  in  some  detail  a  few  of  the  important  systems, 
especially  the  Anderson  iron  process,  the  efficiency  of 
which  we  have  had  ample  opportunity  to  observe  by  ex- 
periments on  a  comparatively  large  scale,  extending  over 
several  months. 

The  favorable  reception  accorded  to  the  first  edition, 
both  by  journals  of  acknowledged  authority,  and  by 
chemists  of  extended  experience  in  this  department,  has 
indicated  that  the  work  is  not  without  usefulness  in  the 
field  to  which  it  is  devoted.  H.  L. 

W.  B. 


CONTENTS. 


HISTORY  AND  CLASSIFICATION  OF  NATURAL  WATERS. 

Rain  Water— Surface  Water— Subsoil  Water— Deep 

Water 13-20 

ANALYTIC  OPERATIONS. 

Sanitary  Examinations : — 

Collection  and  Preliminary  Examination — Total 
Solids — Chlorin — Nitrogen  in  Ammonium  Com- 
pounds  and  Organic  Matter — Nitrogen  as  Nitrates 
— Nitrogen  as  Nitrites — Oxygen-consuming  Power 
—  Phosphates  —  Dissolved  Oxygen  —  Poisonous 

Metals — Biologic  Examinations,      , 21—74 

Technic  Examinations: — 

General  Quantitative  Analysis— Spectroscopic  Anal- 
ysis—Specific Gravity, 74-88 

INTERPRETATION  OF  RESULTS. 

Statement  of  Analysis — Sanitary  Applications — Ac- 
tion of  Water  on  Lead, 89-109 

TECHNIC  APPLICATIONS. 

Boiler    Waters — Sewage    Effluents — Purification   of 

Water — Identification  of  Source  of  Water,    .    .    .109-135 

ADDENDA, I36-»40 

ANALYTIC  DATA. 

Factors  for  Calculation — Conversion  Table — Oxygen 
Dissolved  in  Water— Rain  and  Subsoil  Waters— 
Schuylkill  Water— Artesian  Waters— City  Supplies 
— Culture  Phenomena, 141-149 

INDEX,   151-154 


CORRECTIONS. 


On  page  137,  lines  6  and  5  from  bottom  should  read  "  nutrient  agar- 
agar  of  definite  reaction  (see  below  for  methods  of  determining  re- 
action), to  which  2  to  3  per  " 

On  same  page,  line  2  from  bottom,  for  typhus  read  typhi. 


EXAMINATION  OF  WATER. 


HISTORY  AND  CLASSIFICATION  OF  NATURAL 
WATERS. 

Pure  water  is  an  artificial  product.  Natural  waters 
always  contain  foreign  matters  in  solution  and  suspension, 
varying  from  mere  traces  to  very  large  proportions.  The 
properties,  effects,  and  uses  of  water  are  considerably  modi- 
fied by  these  ingredients,  and  the  object  of  analysis  is  to 
ascertain  their  character  and  amount.  Since  these  are 
largely  dependent  on  the  history  of  the  water,  a  classifica- 
tion based  on  this  will  be  convenient.  We  may  distinguish 
four  classes  of  natural  waters  : — 

Rain  Water. — Water  precipitated  from  the  atmosphere 
under  any  conditions,  and  therefore  including  dew,  frost, 
snow,  and  hail. 

Surface  Water. — All  collections  of  water  in  free  contact 
with  the  atmosphere,  as  in  streams,  seas,  lakes,  or  ponds. 

Subsoil  or  Ground  Water. — Water  not  in  free  contact 
with  the  atmosphere,  percolating  or  flowing  through  soil 
or  rock  at  moderate  distance  below  the  surface,  and 
derived  in  large  part  from  the  rain  or  surface  water  of 
the  district. 

Deep  or  Artesian  Water. — Water  accumulated  at  con- 
siderable depth  below  the  surface,  from  which  the  subsoi 


14  HISTORY    AND    CLASSIFICATION. 

water  of  the  district  has  been  excluded  by  difficultly  per- 
meable strata. 

Rain  Water,  when  gathered  in  the  open  country  and 
in  the  later  period  of  a  long  rain  or  snow,  is  the  purest 
form  of  natural  water.  When  collected  directly,  it  con- 
tains but  little  solid  matter,  this  consisting  principally  of 
ammonium  compounds  and  particles  of  organic  matter, 
living  and  dead,  gathered  from  the  atmosphere.  In  dis- 
tricts near  the  sea  an  appreciable  amount  of  chlorids  will 
be  present.  It  is  obvious  that  a  prolonged  rain  will  wash 
out  the  air,  but  since  storms  are  usually  attended  by  wind, 
fresh  portions  of  air  are  continually  flowing  in,  and  thus 
the  water  never  becomes  perfectly  pure.  Rain  water  col- 
lected in  inhabited  districts  is  usually  quite  impure. 

Surface  Water. — Rain  water  in  part  flows  off  on  the 
surface,  and  gains  in  the  proportion  of  suspended  and  dis- 
solved matters,  the  former  being  found  in  large  amount 
when  the  rainfall  is  profuse.  The  wearing  action  of  water 
is  dependent  on  the  amount  and  character  of  these  sus- 
pended materials.  From  the  higher  levels  of  a  watershed, 
the  streams,  more  or  less  in  the  form  of  torrents,  gather 
into  larger  currents,  and  reaching  lower  levels  become 
slower  in  movement,  and  deposit  much  of  the  suspended 
matter.  By  admixture  of  the  waters  from  widely  separated 
districts  the  character  and  amount  of  the  dissolved  matters 
are  much  modified.  An  action  of  this  kind  is  seen  in  the 
watershed  of  the  Schuylkill  River.  This  stream  rises  in  the 
anthracite-coal  region  of  Pennsylvania,  and  receiving  much 
refuse  mine-water  becomes  impregnated  with  iron  salts  and 
free  mineral  acid,  being  then  quite  unsuitable  for  drinking 
or  manufacturing  purposes.  In  its  course  of  about  one 
hundred  miles  it  passes  over  an  extensive  limestone  dis- 


SUBSOIL   WATER.  15 

trict,  and  receives  several  large  streams  highly  charged  with 
calcium  carbonate.  The  result  is  a  neutralization  of  the 
acid  and  a  precipitation  of  the  iron  and  much  of  the 
calcium.  The  river  becomes  purer,  and  at  its  junction 
with  the  Delaware  River  at  Philadelphia  it  con  tains  neither 
free  sulphuric  nor  hydrochloric  acid,  only  traces  of  iron, 
and  but  a  small  amount  of  calcium  sulphate.  In  this  man- 
ner there  is  produced  a  soft  water,  superior  to  that  of  the 
river  near  its  source,  or  to  the  hard  waters  of  the  middle 
Schuylkill  region. 

It  is  obviously  impossible  to  establish  close  standards  of 
composition  for  surface  waters.  In  the  case  of  rain  water, 
falling  on  the  surface  of  undisturbed,  unpopulated  terri- 
tory, the  amount  of  solids  dissolved  will  be  small,  and 
will  consist  principally  of  carbonates  and  sulphates.  The 
water  of  lakes  and  rivers  is,  however,  in  part  derived  from 
springs,  which  may  proceed  from  great  depths,  and  thus 
introduce  substances  not  easily  soluble  in  surface  water, 
nor  derivable  from  the  soil  of  the  district. 

The  exposure  to  light  and  air  which  surface  water  under- 
goes, results  in  the  absorption  of  oxygen  and  loss  of  car- 
bonic acid,  together  with  the  oxidation  of  the  organic 
matter.  The  diminution  of  the  rapidity  of  the  current 
permits  the  deposition  of  the  suspended  matters,  and  this 
occurs  especially  as  the  river  approaches  the  sea,  not  only 
from  the  retarding  influence  of  the  tidal  wave,  but  from 
the  precipitating  action  of  the  salt  water.  The  investiga- 
tions of  Carl  Barus,  published  in  Bulletin  No.  36,  U.  S. 
Geological  Survey,  have  shown  the  decided  influence  of 
sodium  chlorid  in  accelerating  the  subsidence  of  fine 
particles. 

Subsoil   Water.— Water    that    penetrates    the    soil, 


1 6  HISTORY    AND    CLASSIFICATION. 

passes  to  various  depths,  according  to  the  porosity  and 
arrangement  of  the  strata.  As  a  rule,  it  descends  until  it 
reaches  but  slightly  pervious  formations,  upon  the  level  of 
which  it  accumulates.  In  the  upper  layer  of  soil  it 
dissolves  mineral  and  organic  ingredients,  and  becomes 
impregnated  with  microorganisms,  through  the  agency  of 
which  the  organic  matter  undergoes  important  transforma- 
tions. The  water  constantly  accumulating,  gradually  flows 
along  the  incline  of  the  impervious  stratum,  or  through  its 
fissures,  and  may  either  pass  downward  or  emerge  in  the 
form  of  a  spring. 

The  proportion  of  water  which  may  be  held  by  any 
rock  or  soil  is  often  much  larger  than  would  be  at  first 
supposed.  T.  Sterry  Hunt  states  that  a  square  mile  of 
sandstone  100  feet  thick  will  contain  water  sufficient  to 
sustain  a  flow  of  a  cubic  foot  a  minute  for  more  than  thir- 
teen years. 

Much  difference  is  observed  in  the  composition  of  sub- 
soil waters,  but  as  a  general  rule  they  contain  but  a  limited 
amount  of  mineral  substances,  and  a  very  small  propor- 
tion of  organic  matter.  In  populated  districts,  however, 
a  marked  change  is  produced  through  admixture  with 
water  containing  animal  and  vegetable  products  in  various 
stages  of  decomposition.  It  is  especially  the  organic  mat- 
ter containing  nitrogen  that  is  of  importance.  To  this 
class  belong  all  those  compounds  forming  tissues  that  are 
intimately  associated  with  vital  action ;  also  many  charac- 
teristic excretory  products.  These  bodies  are  mostly 
unstable,  and  as  soon  as  their  vitality  ceases  begin  to 
decompose,  partly  by  oxidation,  partly  by  splitting  up 
into  simpler  forms;  these  changes  being  in  most  cases 
brought  about  by  microorganisms.  Among  the  products 


SUBSOIL   WATER.  17 

noticed  in  the  early  stages  of  such  decay,  are  substances 
which  possess  close  analogies  to  the  organic  bases  or  alka- 
loids, but  more  susceptible  of  decomposition.  They  are 
generally  present  in  minute  amount,  but  are  not  infre- 
quently very  active  in  their  physiological  effect.  From 
the  most  recent  researches  it  seems  probable  that  the 
pathogenic  power  of  many  microorganisms  rests  not  upon 
any  mechanical  or  other  action  of  the  germs  themselves, 
but  upon  the  alkaloidal  principles  which  they  produce  and 
excrete.  As  a  group  these  bodies  are  known  as  the 
"  ptomains."  Nitrogen  is  an  invariable  ingredient.  The 
ultimate  results  of  the  processes  of  decomposition  depend 
largely  on  circumstances.  When  organic  matters  contain- 
ing nitrogen  are  subjected  to  the  action  of  oxidizing 
agents,  such  as  alkaline  potassium  permanganate  or 
chromic  acid,  some  of  the  nitrogen  is  converted  into 
ammonium  compounds.  A  similar  result  occurs  in  all 
waters,  but  a  considerable  portion  of  the  organic  matter 
may  also  suffer  further  oxidation,  and  in  association  with 
the  mineral  substances  present  form  nitrites  and  nitrates, 
especially  the  latter.  This  conversion  is  called  "  nitrifi- 
cation." The  conditions  under  which  it  occurs  have 
been  carefully  studied  by  various  observers,  but  much 
research  is  still  needed  to  place  the  subject  on  a  secure 
basis. 

Nitrification  takes  place  under  the  influence  of  microbes, 
the  habitat  of  which  does  not  extend  more  than  a  few 
yards  below  the  surface  of  the  soil.  Percy  and  Grace 
Frankland  have  isolated  and  described  a  bacillus  with  active 
nitrifying  powers.  It  is  a  very  short,  almost  spherical 
form,  which  grows  in  ammoniacal  culture-fluids  and  in 
meat-broth,  but  does  not  grow  in  the  usual  gelatin-peptone 


1 8  HISTORY   AND    CLASSIFICATION. 

mixture,  except  when  previously  cultivated  in  meat-broth. 
The  nitrifying  action  is  probably  exerted  only  upon  the 
ammonium  which  is  formed  from  the  organic  matter.  The 
presence  of  some  substance  capable  of  neutralizing  acids  is 
necessary  to  continuous  action.  Calcium  and  magnesium 
carbonates  fulfill  this  function.  Nitrates  are  the  final  result 
of  this  action  ;  nitrites  are  present  at  any  given  time  only 
in  small  quantity.  Denitrification,  that  is,  the  reduction 
of  nitrates  and  nitrites  to  ammonium  compounds,  takes 
place  also  under  the  influence  of  microbes,  and  is  especially 
apt  to  occur  when  considerable  quantities  of  decomposing 
organic  matter  are  introduced.  Percy  and  Grace  Frank- 
land  have  described  several  species  of  bacilli  which  have 
active  denitrifying  powers.  Among  these  are  Bacillus 
liquidus,  B.  vetmicularis,  and  B.  ramosus.  A  partial 
reduction  sometimes  occurs,  and  a  notable  proportion 
of  nitrites  is  found,  but  in  the  presence  of  actively  de- 
composing organic  matter,  such  as  that  in  sewage,  a 
complete  reduction,  even  to  the  liberation  of  nitrogen, 
may  occur.  Jordan  (Rep.  S.  B.  of  H.,  of  Mass.,  1890), 
has  described  several  species,  found  in  the  sewage  of  the 
city  of  Lawrence,  which  reduce  nitrates  rapidly  to  nitrites. 
Deep  Water. — Water  which  penetrates  the  fissures  of 
the  fundamental  rock  formations  may  pass  to  great  depths, 
and  by  following  the  lines  of  the  lowest  and  least  permeable 
strata  may  be  transported  to  points  far  removed  from  those 
at  which  it  was  originally  collected.  The  chemical  changes 
thus  induced  include  most  of  those  which  take  place  at 
higher  points,  but  the  increase  of  pressure  and  temperature 
confers  increased  solvent  power.  Carbonic  acid  will 
accumulate  under  conditions  favorable  to  the  solution  of 
calcium,  magnesium,  and  iron  carbonates,  and  iron  and 


DEEP   WATER.  1 9 

manganese  oxids  may  be  converted  into  carbonates  and 
then  dissolved.  Sulphates  are  reduced  to  sulphids,  and 
these  subsequently,  by  the  action  of  carbonic  acid,  yield 
hydrogen  sulphid.  Organic  matter,  living  and  dead,  plays 
an  important  part,  determining  the  reduction  of  ferric 
compounds  to  ferrous,  and  of  the  sulphates  to  sulphids,  and 
is  itself  converted  ultimately  into  ammonium  compounds, 
notable  quantities  of  which  are  often  found  in  deep  waters. 
Further,  it  is  found  that  nitrates  and  nitrites  are  present 
only  in  small  amount,  except  from  certain  strata  rich  in 
organic  matter.  In  some  cases  the  water  acquires  very 
high  temperature,  and  dissociation  of  rocks  occurs  with 
solution  of  considerable  amounts  of  silicic  acid,  which  is 
ordinarily  but  sparingly  soluble  in  water. 

Masses  of  water  thus  accumulated  under  heat  and  pres- 
sure may  find  their  way  to  the  surface  either  through 
natural  fissures,  or  be  reached  by  borings.  The  mineral 
springs,  highly  charged  with  solid  matters,  and  the  artesian 
waters  are  obtained  in  this  way. 

While  no  absolute  unchangeable  line  can  be  drawn  be- 
tween deep  and  subsoil  waters,  yet  it  will  in  most  cases  be 
found  that  the  deep  water  of  a  given  district,  whether 
obtained  through  natural  or  artificial  channels,  will  be 
decidedly  different  in  composition  from  the  subsoil  or  sur- 
face water  of  the  same,  and  that  the  rocks  passed  through 
in  such  cases  will  be  characterized  by  one  or  more  strata, 
difficultly  permeable  to  water,  and  therefore  preventing 
direct  communication.  The  characteristic  differences  be- 
tween surface,  subsoil,  and  deep  waters  are  clearly  indi- 
cated in  the  table  of  analyses  given  in  the  appendix. 

The  fact  that  mere  depth  is  not  the  essential  difference 
between  the  two  classes  of  waters  is  shown  by  comparison 


20  HISTORY   AND    CLASSIFICATION. 

between  the  composition  of  the  water  from  the  well  at 
Barren  Hill,  on  the  northern  border/of  Philadelphia 
county,  and  the  deep  well  at  Locust  Point,  Baltimore. 
The  former  is  a  dug  well,  130  feet  deep;  the  latter  is  an 
artesian  boring  of  128  feet,  which  in  its  descent  passes 
through  four  feet  of  solid  rock.  The  deeper  welt  is  evi- 
dently supplied  by  subsoil  water.  The  artesian  well, 
though  located  100  yards  from  a  brackish  sewage-laden 
estuary,  evidently  derives  no  water  from  it. 


ANALYTIC   OPERATIONS. 


SANITARY    EXAMINATIONS. 

COLLECTION     AND     PRELIMINARY     EXAMINATION 

OF  SAMPLES. 

Great  care  must  be  taken  in  collecting  water-samples, 
in  order  to  secure  a  fair  representation  of  the  supply 
and  to  avoid  introduction 
of  foreign  matters.  The 
five-pint  green  glass  stop- 
pered bottles  used  for 
holding  acids  are  suitable 
for  containing  the  sam- 
ples. The  contents  of 
one  such  bottle  will  suf- 
fice for  most  sanitary  or 
technical  examinations. 
Fig.  i  shows  a  boxed  bot- 
tle known  as  "  Banker's 
Glass  Can,"  which  I  have 
found  very  convenient 
for  transportation.  It  is 
provided  with  a  hinged 

lid  which  can  be  fastened,  if  deemed  necessary,  by  a 
padlock.  The  green-glass  stoppered  bottles  may  be  fitted 
in  such  an  arrangement.  Stone  jugs,  casks,  or  metal 
vessels  must  not  be  employed.  The  bottles  used  must  be 
21 


22  ANALYTIC   OPERATIONS. 

thoroughly  rinsed  several  times  with  the  water  to  be  ex- 
amined, filled  and  the  stopper  tied  down,  or  fastened  by 
stretching  a  rubber  finger-cot  over  the  stopper  and  lip.  If 
corks  are  used,  they  should  be  new  and  thoroughly  rinsed. 
Wax,  putty,  plaster,  or  similar  material  should  not  be 
used. 

In  taking  samples  from  lakes,  slow  streams,  or  reservoirs, 
it  is  necessary  to  submerge  the  bottle  so  as  to  avoid  col- 
lecting any  water  that  has  been  in  immediate  contact  with 
the  air. 

In  the  examination  of  public  water  supplies,  the  sample 
should  be  drawn  from  a  hydrant  in  direct  connection  with 
the  main,  and  not  from  a  cistern,  storage  tank,  or  dead 
end  of  a  pipe.  In  the  case  of  pump-wells,  a  few  gallons 
of  water  should  be  pumped  out  before  taking  the  sample, 
in  order  to  remove  that  which  has  been  standing  in  the 
pipe. 

In  all  cases  care  should  be  taken  to  fill  the  vessel  with 
as  little  agitation  with  air  as  possible. 

It  is  important  that  with  each  sample  a  record  be  made 
of  those  surroundings  and  conditions  which  might  influ- 
ence the  character  of  the  water,  particularly  in  reference 
to  sources  of  pollution,  such  as  proximity  to  cesspools, 
sewers,  or  manufacturing  establishments.  The  character 
and  condition  of  the  different  strata  of  the  locality  should 
be  noted  if  possible. 

Determinations  of  nitrogen  existing  as  ammonium  com- 
pounds, and  as  organic  matter,  and  of  oxygen-consuming 
power,  should  be  made  upon  the  sample  in  the  original 
condition,  whether  turbid  or  clear,  but  all  other  estima- 
tions should  be  made  upon  the  clear  liquid.  Turbid  waters 
may  be  clarified  by  standing  or  by  filtration  ;  for  the  latter 


SANITARY    EXAMINATIONS.  23 

purpose  Schleicher  &  Schiill's  extra-heavy  No.  598  paper 
is  the  best.  In  many  cases  the  suspended  matter  cannot 
be  entirely  removed  by  filtration,  and  subsidence  must  be 
resorted  to.  The  use  of  a  small  quantity  of  alum,  or 
aluminum  hydroxid,  as  described  in  the 'section  on  the 
purification  of  water,  will  sometimes  be  applicable  as  a 
means  of  clarifying  samples.  For  the  quantitative  deter- 
mination, the  sediment  from  a  known  volume  of  the  water 
is  collected  on  a  tared  filter,  dried  at  112°  F.,  and  weighed. 

The  water  from  newly-dug  wells  is  generally  turbid  and 
the  determinations  are  best  made  after  filtration,  but  the 
results  will  be  unsatisfactory,  showing  a  higher  proportion 
of  organic  matter  than  will  be  found  when  the  supply  be- 
comes clear. 

The  following  methods  of  determining  color  and  odor 
have  been  adopted  by  the  Society  of  Public  Analysts  of 
Great  Britain  : — 

Color. — A  colorless  glass  tube,  two  feet  long  and  two 
inches  in  diameter,  is  closed  at  each  end  with  a  disc  of 
colorless  glass.  An  opening  for  filling  and  emptying  the 
tube  should  be  made  at  one  end,  either  by  cutting  a  small 
segment  off  the  glass  disc,  or  cutting  out  a  small  segmental 
section  of  the  tube  itself  before  the  disc  is  cemented  on. 
A  good  cement  for  such  purposes  is  the  following  :  — 

Caoutchouc, 2  parts. 

Mastic 6     " 

Chloroform loo     " 

The  ingredients  are  mixed  and  allowed  to  stand  for  a 
few  days.  The  cement  should  be  used  as  soon  as  solution 
is  effected,  as  it  becomes  viscid  on  standing. 

The  tube  must  be  about  half  filled  with  the  water  to  be 
examined,  brought  into  a  horizontal  position,  level  with 


24  ANALYTIC   OPERATIONS. 

the  eye,  and  directed  toward  a  brightly  illuminated  white 
surface.  The  comparison  of  tint  has  to  be  made  between 
the  lower  half  of  the  tube  containing  the  water  under  ex- 
amination, and  the  upper  half  containing  air  only. 

By  determining  the  amount  of  ammonium  chlorid  re- 
quired to  produce  with  a  standard  quantity  of  Nessler  solu- 
tion a  color  equal  in  depth  to  that  of  the  water-sample,  a 
means  of  recording  the  color  with  some  precision  may 
often  be  obtained.  The  manipulation  is  conducted  as  de- 
scribed in  connection  with  the  determination  of  ammonium 
compounds,  using  equal  volumes  of  the  sample  and  of  dis- 
tilled water  in  separate  cylinders.  The  Nessler  solution 
is,  of  course,  added  only  to  the  distilled  water.  The 
volume  of  diluted  standard  ammonium  chlorid  solution 
which  must  be  added  to  the  distilled  water  to  enable  it 
to  produce  with  the  Nessler  reagent  a  color  equal  to  that 
of  the  sample  is  taken  as  an  index  of  the  color  of  the 
latter.  Thus  "color  —  0.3  "  means  that  the  color  of  the 
sample  equals  that  produced  by  Nessler  solution  in  distilled 
water  to  which  0.3.  c.  c.  of  the  diluted  standard  ammonium 
chlorid  solution  has  been  added. 

Odor. — Put  about  150  c.  c.  of  the  water  into  a  clean, 
wide-mouth  250  c.  c.  stoppered  bottle,  which  has  been 
previously  rinsed  with  the  same  water  ;  insert  the  stopper 
and  warm  the  water  in  a  water-bath  to  100°  F.  Remove 
the  bottle  from  the  water-bath  and  shake  it  rapidly  for  a 
few  seconds  ;  remove  the  stopper  and  immediately  note  if 
the  water  has  any  smell.  Insert  the  stopper  and  repeat  the 
test. 

In  a  polluted  water  the  odor  will  sometimes  give  a  clue 
to  the  origin  of  the  pollution. 

Reaction. — The  determination  of  reaction  is  usually 


SANITARY    EXAMINATIONS.  25 

made  by  the  addition  of  a  neutral  solution  of  litmus  to  the 
water.  If  an  acid  reaction  is  obtained  the  water  should 
be  boiled  in  order  to  determine  if  it  is  due  to  carbonic 
acid.  Some  of  the  more  delicate  indicators,  such  as 
phenolphthalei'n  and  lacmoid,  may  be  used  with  advantage 
for  these  tests.  The  latter  possesses  the  advantage  that  it 
is  unaffected  by  carbonic  acid,  but  detects  even  traces  of 
free  mineral  acid.  It  is  neutral,  also,  to  many  normal 
metallic  salts,  such  as  ferrous  sulphate,  which  are  acid  to 
litmus.  Ferric  salts,  however,  are  acid  to  lacmoid.  Its 
color  changes  are  the  same  as  those  of  litmus,  i.  <?.,  red 
with  acids  and  blue  with  alkalies. 

Phenolphthale'in  is  best  applied  to  the  detection  of  weak 
acids,  such  as  carbonic  acid  and  the  organic  acids.  In 
acid  and  neutral  solutions  it  is  colorless — in  alkaline,  deep 
red.  Nearly  all  waters  contain  carbonic  acid,  and  will 
therefore  bleach  a  solution  of  phenolphthalei'n  which  has 
been  reddened  by  a  small  amount  of  alkali. 

TOTAL  SOLIDS. 

A  platinum  basin  holding  zoo  c.  c.  will  be  found  con- 
venient for  this  determination.  This  should  weigh  about 
45  grams.  It  should  be  kept  clean  and  smooth  by  frequent 
burnishing  with  sand,  a  little  of  which  should  be  placed  in 
the  palm  of  the  hand,  moistened,  and  the  dish  gently 
rubbed  against  it.  Very  fine-  sea-sand  with  round,  smooth 
grains,  is  the  only  kind  suitable  for  this  purpose.  Coarse 
river-sand,  tripoli,  or  other  rough  scouring-powders,  must 
not  be  employed.  If  proper  care  is  taken,  the  lustre  of 
the  metal  will  remain  unimpaired  indefinitely,  and  the  loss 
in  weight  will  be  trifling.  The  inner  surface  can  generally 
be  cleaned  by  treatment  with  hydrochloric  acid,  rinsing 


26  ANALYTIC    OPERATIONS. 

and,  if  necessary,  burnishing.  Neglect  of  these  pre- 
cautions will  soon  lead  to  serious  damage  to  the  dish.  A 
small,  smooth  slab  of  iron  or  marble  is  convenient  to  set 
it  on  while  cooling.  When  being  heated  over  the  naked 
flame  the  dish  should  rest  on  a  triangle  of  iron  wire, 
covered  with  pipe-stems.  Dishes  of  pure  nickel  are  not 
satisfactory  substitutes  for  those  of  platinum. 

Platinum-pointed   forceps  should  be  used  in  handling 
the  dish.     The  platinum  terminals  may  be  kept  bright  and 
clean  by  the  use  of  sand. 

FIG.  2.  * 

The  low-temperature  burner, 
used  as  shown  in  Fig.  2,  will  be 
found  a  very  convenient  substi- 
tute for  the  water-bath  and  hot 
air  oven.  The  inlet  pipe  is  very 
short  and  soon  becomes  so  hot 
as  to  injure  the  rubber  tube.  To 
avoid  this  it  may  be  lengthened 
by  means  of  a  piece  of  ^j-inch 
gas-pipe,  or  the  junction  may  be 
wrapped  with  a  rag,  the  ends  of  which  dip  into  water. 
By  capillary  attraction  the  rag  is  kept  moist  and  cool. 

The  determination  of  total  solids  is  made  by  evaporating 
100  or  200  c.  c.  of  the  water  in  the  platinum  basin,  which 
has  been  previously  heated  almost  to  redness,  allowed  to 
cool  for  ten  minutes,  and  weighed.  The  operation  is 
conducted  at  a  moderate  heat.  When  the  residue  appears 
dry,  the  heat  may  be  increased  slightly  for  some  minutes. 
The  above  method  will  answer  in  most  cases.  In  waters 
of  exceptional  purity  it  may  be  advisable  to  use  larger 
quantities,  such  as  250  c.  c.  When  the  residue  contains 
deliquescent  bodies,  the  determination  will  not  be  accurate, 


SANITARY    EXAMINATIONS.  27 

and  when  appreciable  amounts  of  magnesium  and  chlorin 
are  present,  a  decomposition  will  occur  toward  the  close 
of  the  evaporation  by  which  magnesium  oxid  will  be 
formed  and  hydrogen  chlorid  escape. 

The  irregular  decomposition  occurring  during  the  evap- 
oration may  be  largely  prevented  by  adding  .005  gm.  of 
sodium  carbonate  to  each  100  c.  c.  of  the  sample  taken. 
This  converts  magnesium  and  calcium  salts  into  carbonates. 
The  sodium  carbonate  is  conveniently  kept  in  the  form  of 
solution  of  such  strength  that  i  c.  c.  contains  .001  gm. 
The  weight  of  the  carbonate  is  of  course  to  be  deducted 
from  the  weight  of  the  residue.  Drown  and  Hazen  have 
carefully  investigated  this  method  and  have  found  it  avail- 
able for  a  more  satisfactory  determination  of  the  loss  on 
ignition.  For  this  process  they  place  the  platinum  basin 
containing  the  residue  within  another  similar  basin  of  such 
size  that  an  air-space  of  about  one-half  inch  is  left  all 
around  the  inner  dish,  which  is  supported  upon  a  spiral  of 
platinum  that  rests  on  the  bottom  of  the  outer  dish.  Over 
the  inner  dish  is  suspended  a  disc  of  platinum  foil  to 
reflect  the  heat.  The  outer  dish  is  heated  to  bright  red- 
ness. 

After  the  weight  of  the  residue  is  obtained,  the  dish 
should  be  cautiously  heated  to  low  redness,  and  the  effect 
noted.  Nitrates  and  nitrites,  calcium  and  magnesium 
carbonates  are  decomposed  ;  ammonium  salts  are  driven 
off;  potassium  and  sodium  chlorids  are  also  driven  off  if 
the  temperature  is  high.  Organic  matter  is  at  first 
charred,  and  by  continued  heating  burned  off.  When  the 
quantity  of  nitrates  is  considerable,  slight  deflagration  may 
be  observed,  or  the  production  of  red  fumes  of  nitrogen 
dioxid.  The  organic  matter,  in  decomposing,  not  infre- 


28  ANALYTIC   OPERATIONS. 

quently  develops  odors  which  indicate  its  character  or 
source.  These  are  more  satisfactorily  observed  when  a 
rather  large  quantity,  say  250  c.  c.,  is  evaporated  at  a  low 
heat,  preferably  on  a  water-bath. 

In  water  of  high  organic  purity,  the  residue  on  heating 
will  give  no  appreciable  blackening  nor  odor,  while  in 
forest  streams  charged  with  vegetable  matter  derived  from 
falling  leaves,  very  decided  blackening  without  unpleasant 
odor  will  be  noticed.  The  loss  of  weight  after  heating 
cannot  be  taken  as  a  measure  of  the  organic  matter,  except 
when  present  in  relatively  large  amount. 

CHLORIN. 
Solutions  Required  : — 

Standard  Silver  Nitrate. — Dissolve  about  five  grams  of 
pure  recrystallized  silver  nitrate  in  distilled  water,  and 
make  the  solution  up  to  1000  c.  c.  The  amount  of  chlorin 
to  which  this  is  equivalent  may  be  determined  as  follows : 
Several  grams  of  pure  sodium  chlorid  are  finely  powdered 
and  heated  over  a  Bunsen  burner  for  five  minutes,  not  quite 
to  redness.  When  cold,  0.824  gram  is  dissolved  in  water 
and  the  solution  made  up  to  500  c.  c.  25  c.  c.  of  this 
should  be  treated  as  below,  and  the  amount  of  silver  solu- 
tion required  noted.  Each  c.  c.  of  the  sodium  chlorid 
solution  is  equivalent  to  .001  gram  chlorin. 

Potassium   Chromate. — Five  grams   of  potassium  chro- 
mate  are  dissolved  in  100  c.  c.  of  distilled  water.     A  solu- 
tion  of  silver  nitrate   is  added   until  a   permanent  red 
precipitate  is  produced,  which  is  separated  by  filtration. 
Analytic  Process :  — 

If  a  preliminary  test  shows  the  chlorin  to  be  present  in 
considerable  amount,  the  determination  may  be  made  on 


SANITARY    EXAMINATIONS.  29 

ioo  c.  c.  of  the  water  without  concentration.  If,  how- 
ever, there  is  but  little  present,  250  c.  c.  should  be  evap- 
orated to  about  one-fifth,  best  with  the  addition  of  a  little 
sodium  carbonate,  and  the  determination  made  on  the 
concentrated  liquid  after  cooling. 

The  water  is  placed  in  a  porcelain  dish  or  in  a  beaker 
standing  on  a  white  surface,  a  few  drops  of  potassium 
chromate  solution  added,  and  standard  silver  nitrate  solu- 
tion run  in  from  a  burette  until  a  faint  red  color  of  silver 
chromate  remains  permanent  on  stirring.  The  proportion 
of  chlorin  is  then  calculated  from  the  number  of  c.  c. 
of  silver  solution  added.  For  greater  accuracy  a  second 
determination  may  be  made,  using  as  a  comparison  the 
liquid  first  titrated,  the  red  color  having  been  previously 
discharged  by  a  few  drops  of  sodium  chlorid  solution. 

The  water  should  always  be  as  nearly  neutral  as  possible 
before  titration.  If  acid,  it  may  be  neutralized  by  the 
addition  of  sodium  carbonate. 

The  residue  obtained  by  evaporating  the  water  with 
sodium  carbonate  as  described  in  connection  with  the  de- 
termination of  the  total  solids  will  serve  conveniently  for 
estimating  the  chlorin.  It  is  best  to  use  200  c.  c.  of  the 
sample  and  redissolve  the  residue  in  about  50  c.  c.  of 
distilled  water,  rubbing  the  sides  of  the  dish  well  with  a 
rubber-tipped  rod,  and  then  titrating  as  indicated  above. 

NITROGEN    IN    AMMONIUM   COMPOUNDS    AND    IN    OR- 
GANIC MATTER. 

The  nitrogen  in  ammonium  compounds,  and  a  part  of 
that  in  the  organic  matter,  is  determined  by  a  process  of 
distillation  first  developed  fully  by  Messrs.  Wanklyn, 
Chapman,  and  Smith.  It  depends  upon  the  conversion  of 


3° 


ANALYTIC   OPERATIONS. 


the  nitrogen  into  ammonium  compounds  and  subsequent 
estimation  in  the  distillate. 
Apparatus  Required : — 

Distilling  Apparatus. — That  shown  in   Fig.  3  has  been 
found  to  be  the  most  convenient.     The  still  consists  of  a 

FIG.  3. 


Bohemian  glass  retort  of  about  1000  c.  c.  capacity.  The 
beak  of  the  retort  should  incline  slightly  upward,-  to 
prevent  contamination  by  splashing.  At  about  two  inches 
from  the  end  it  should  be  bent  at  a  right  angle,  and  drawn 
out  so  as  to  enter  the  condensing  worm  for  about  an  inch, 


SANITARY    EXAMINATIONS.  3! 

and   terminate  beneath   the  level  of    the   water.      Glass 
worms  are  apt  to  crack,  and  it  is  more  satisfactory  to  use 


one  of  block  tin.  A  piece  of  rubber  tubing  is  drawn  over 
the  junction.  A  rapid  current  of  cold  water  should  be  main- 
tained through  the  condenser.  The  heat  is  applied  by 


32  ANALYTIC   OPERATIONS. 

means  of  the  low-temperature  burner,  the  iron  ring  of 
which  is  removed  so  that  the  retort  rests  directly  on  the 
gauze.  With  this  arrangement  the  heat  is  under  perfect 
control,  and  the  danger  of  fracturing  the  glass  is  reduced 
to  a  minimum.  It  is  advisable  to  protect  the  retort  from 
drafts  of  cold  air. 

Another  convenient  form  of  apparatus  is  shown  in  Fig. 
4.  It  is  employed  in  the  laboratory  of  the  Massachusetts 
State  Board  of  Health.  (A.  H.  Gill,  The  Analyst,  xvin.) 

Cylinders  for  Comparison- Color  Tests,  about  2.5  cm.  in 
diameter  and  holding  too  c.  c.,  made  of  colorless  glass. 
Solutions  Required  : — 

Sodium  Carbonate. — 50  grams  of  pure  sodium  carbonate 
are  strongly  heated,  dissolved  in  250  c.  c.  of  distilled 
water,  and  the  solution  boiled  down  to  200  c.  c. 

Ammonium-Free  Water. — If  the  distilled  water  of  the 
laboratory  gives  a  reaction  with  Nessler  reagent,  it  should 
be  treated  with  sodium  carbonate,  about  one  grain  to  the 
liter,  and  boiled  until  about  one-fourth  has  been  evapor- 
ated. Ammonium-free  water  may  be  obtained  by  distill- 
ing, in  a  retort,  water  made  slightly  acid  with  sulphuric 
acid. 

Standard  Ammonium  Chlorid. — Dissolve  0.382  gram  of 
pure  dry  ammonium  chlorid  in  100  c.  c.  of  ammonium- 
free  water.  For  use,  dilute  i  c.  c.  of  this  solution  with 
pure  water  to  100  c.  c.  i  c.  c.  of  this  dilute  solution  con- 
tains .00001  gram  of  nitrogen. 

Nessler  Reagent. — Dissolve  35  grams  of  potassium  iodid 
in  100  c.  c.  of  water.  Dissolve  17  parts  of  mercuric  chlorid 
in  300  c.  c.  of  water.  The  liquids  may  be  heated  to  aid 
solution,  but  must  be  cooled  before  use.  Add  the  mercuric 
chlorid  solution  to  that  of  the  potassium  iodid,  until  a  per- 


SANITARY   EXAMINATIONS.  33 

manent  precipitate  is  produced.  Then  dilute  with  a  20 
per  cent,  solution  of  sodium  hydroxid  to  1000  c.  c.,  add 
mercuric  chlorid  solution  until  a  permanent  precipitate 
again  forms  and  allow  to  stand  until  clear.  Nessler  and 
other  reagents  are  best  kept  in  glass-capped  bottles,  Fig. 
5,  in  which  the  pipette  may  remain  when  not  in  use.  The 
solution  improves  by  keeping. 

Alkaline  Potassium   Permanganate. — Dissolve      FlG-  5' 
200  grams  of  potassium  hydroxid,  in  sticks,  and 
eight  grams  of  potassium  permanganate,  in  a  liter 
of  distilled  water. 

The  solution  may  be  boiled  until  about  one- 
fourth  is  evaporated  and  then  made  up  to  a  liter 
with  ammonium-free  water.  It  will  still  furnish 
some  ammonium.  Fox  recommends  to  distill  50 
c.  c.  with  500  c.  c.  of  absolutely  ammonium-free  water, 
best  twice  distilled  with  sulphuric  acid,  and  note  the 
ammonia  obtained.  This  quantity  should  be  deducted  in 
each  analysis.  The  method  of  determining  nitrogen  by 
permanganate,  as  recommended  by  the  A.  A.  A.  S., 
avoids  the  necessity  for  this  preliminary  valuation  of  the 
solution. 
Analytic  Process : — 

The  retort  and  condenser  are  thoroughly  rinsed  with 
ammonium- free  water,  500  c.  c.  of  the  water  to  be  tested 
introduced,  about  five  c.  c.  of  the  sodium  carbonate  solu- 
tion added  to  render  the  water  alkaline,  and  a  piece  of 
pumice-stone  heated  to  redness  and  dropped  in  while  hot. 
The  water  is  then  boiled  gently  until  the  distillate  meas- 
ures 50  c.  c.  The  distillate  is  transferred  to  one  of  the 
color-comparison  cylinders  and  two  c.  c.  of  Nessler 
reagent  added.  A  yellowish-brown  color  is  produced,  the 
c 


34  ANALYTIC   OPERATIONS. 

intensity  of  which  is  proportional  to  the  amount  of  am- 
monium present.  The  full  color  is  developed  in  five 
minutes.  This  color  is  exactly  matched  by  introducing 
into  another  cylinder  50  c.  c.  of  ammonium-free  water, 
some  of  the  standard  ammonium  chlorid  solution,  and  two 
c.  c.  Nessler  reagent,  as  before.  According  as  the  color 
so  produced  is  deeper  or  lighter  than  that  obtained  from 
the  water,  other  comparison  liquids  are  prepared  contain- 
ing smaller  or  larger  proportions  of  the  ammonium 
chlorid,  until  the  proper  color  is  produced. 

The  distillation  is  continued,  successive  portions  of  50 
c.  c.  each  collected,  and  tested  until  no  reaction  occurs 
with  Nessler  reagent.  The  sum  of  the  figures  from  the 
several  distillates  gives  the  total  nitrogen  obtainable  as 
"  free  ammonia,"  so-called. 

If  the  quantity  of  ammonium  is  sufficient  to  cause  a 
precipitate,  the  color  comparison  cannot  be  accurately 
made.  In  most  cases  this  will  not  be  of  serious  moment, 
as  the  quantity  will  be  beyond  the  allowable  limit.  If 
accurate  determination  be  desired,  it  may  be  made  by 
dividing  the  first  distillate  into  two  equal  parts,  nessleriz- 
ing  one  of  these,  and  then,  if  necessary,  diluting  the 
second  part  with  ammonium-free  water  and  nesslerizing 
this. 

Occasionally  the  evolution  of  ammonium  hydroxid 
continues  indefinitely,  and  may  even  increase  with  succes- 
sive distillates.  This  is  due,  not  to  ammonium  compounds 
existing  as  such,  but  to  decomposition  of  certain  nitro- 
genous bodies,  especially  urea.  In  this  case,  it  is  not 
advisable  to  prolong  distillation  beyond  the  fourth  or  fifth 
distillate,  but  to  proceed  to  the  following  part  of  the 
process. 


SANITARY    EXAMINATIONS.  35 

The  residue  in  the  retort  serves  for  the  determination 
of  the  nitrogen  which  is  convertible  into  ammonium 
by  alkaline  potassium  permanganate — the  so-called  "albu- 
minoid ammonia"  of  Messrs.  Wanklyn,  Chapman,  and 
Smith. 

Fifty  c.  c.  of  alkaline  permanganate  solution  are  added 
to  the  retort,  the  distillation  resumed,  and  the  nitrogen 
estimated  in  each  50  c.  c.  as  before,  deducting  that 
yielded  by  the  permanganate. 

It  is  the  practice  of  some  analysts  to  mix  the  distillates 
of  each  of  the  above  operations,  and  thus  make  deter- 
minations merely  of  the  total  nitrogen  in  each  case.  By 
so  doing  valuable  information  may  be  lost,  since  it  has 
been  pointed  out  by  several  observers,  notably  Mallet  and 
Smart,  that  important  information  may  be  gained  by 
observing  the  rate  of  evolution  of  the  ammonium  hy- 
droxid.  Mallet  has  further  pointed  out  that  many  waters 
may  contain  substitution  ammoniums  which  may  pass  over 
before  the  addition  of  the  alkaline  permanganate,  but  not 
be  correctly  measured  by  nesslerizing.  To  avoid  this 
source  of  error,  he  suggested  that  two  determinations  be 
made  on  each  sample,  one  as  above  described  and  the 
other  by  the  addition  of  alkaline  permanganate  without 
previous  distillation.  In  this  manner  a  higher  figure  will 
often  be  obtained  than  the  sum  of  the  figures  from  the 
two  distillations  by  the  other  process. 

Since  small  quantities  of  ammonium  compounds  and 
nitrogenous  matters  are  everywhere  present,  the  greatest 
care  should  be  exercised  in  order  to  avoid  their  introduc- 
tion in  any  way  during  the  course  of  the  analysis.  All 
measuring  vessels,  cylinders,  etc.,  should  be  thoroughly 
rinsed  before  using.  The  temperatures  of  the  distillates 


36  ANALYTIC   OPERATIONS. 

and  standards  should  be  approximately  the  same  when  the 
colors  are  compared. 

The  Chemical  Section  of  the  American  Association  for 
the  Advancement  of  Science  recommends  the  following 
method  for  the  application  of  the  process  embodying  the 
results  of  recent  investigations:  — 

"  Two  hundred  c.  c.  of  distilled  water,  together  with  10 
c.  c.  of  the  sodium  carbonate  solution,  are  distilled  down 
to  about  100  c.  c.  in  the  retort  in  which  the  analysis  is  to 
be  conducted,  and  the  last  portion  of  50  c.  c.  nesslerized 
to  assure  freedom  from  ammonium.  Then  500  c.  c.  of  the 
water  to  be  examined  are  added  and  the  distillation  is 
carried  on  at  such  a  rate  that  about  50  c.  c.  are  collected 
in  each  succeeding  ten  minutes,  and  until  a  50  c.  c.  meas- 
ure of  distillate  is  obtained  containing  only  an  inappre- 
ciable quantity  of  ammonia.  In  nesslerizing,  five  minutes 
are  to  be  allowed  for  the  full  development  of  color ; 
after  this,  no  change  takes  place  for  many  hours. 

"  Now  throw  out  the  contents  of  the  retort,  rinse  it 
thoroughly,  put  in  200  c.  c.  of  distilled  water  and  50  c.  c. 
of  the  permanganate  solution,  distill  down  to  about  100 
c.  c.,  and  nesslerize  the  last  portion  of  50  c.  c.,  to  make 
sure  of  freedom  from  ammonia ;  add  another  portion  of 
500  c.  c.  of  the  water  under  examination  and  proceed 
with  the  distillation  and  nesslerizing  as  with  the  first 
portion. 

"The  difference  between  the  'free'  ammonia  of  the 
first  operation  and  the  total  ammonia  of  the  second,  is  to 
be  taken  as  the  'albuminoid'  ammonia." 

Bachman  has  described  (Jour,  of  Amer.  Chem.  Soc., 
April,  1895)  a  process  for  determining  nitrogen  by  per- 
manganate by  using  an  apparatus  which  permits  of  the 


SANITARY    EXAMINATIONS.  37 

addition  of  the  water  in  small  and  limited  quantity  to 
the  full  strength  of  permanganate  solution  at  about  the 
rate  of  distillation,  so  that  at  no  time  does  it  act  upon  a 
large  volume.  The  apparatus  consists  of  a  flask  of  one 
liter  capacity,  fitted  by  a  ground  joint  to  a  hollow  cap 
carrying  two  upright  tubes,  each  provided  with  a  stop- 
cock, and  to  which  cap  also  is  attached  the  tube  through 
which  the  distilled  vapors  pass  to  the  condenser.  Of  the 
two  upright  tubes,  one  has  a  capacity  of  50  c.  c.,  and  its 
end  reaches  through  the  cap  to  within  three  inches  of  the 
bottom  of  the  distillation  flask.  The  other  has  a  capacity 
of  250  c.  c.,  and  its  tube  projects  to  within  one-half  of 
the  bottom.  The  condensing  apparatus  is  a  closely-coiled 
glass  worm,  with  a  long  projection  at  the  lower  extremity 
which  passes  through  a  soft  rubber  cork,  inserted  in  a 
receiver.  Through  this  cork  also  there  is  connected  a 
Will  and  Varrentrap  ammonium-absorption  bulb.  All  con- 
nections should  be  tight  without  the  use  of  a  lubricant. 
The  arrangement  can  be  made  movable  so  as  to  be  raised 
from  the  bath  if  necessary.  Bach  man  employs  a  bath  of 
salt  water,  but  it  is  not  unlikely  that  a  low  temperature 
burner  would  answer  every  purpose. 

The  procedure  is  as  follows  :  After  thoroughly  rinsing 
the  apparatus  with  ammonium-free  distilled  water,  500  c.  c. 
of  the  water  under  examination  with  the  addition  of  a 
little  sodium  carbonate  if  needed,  are  put  into  the  flask. 
The  Will  and  Varrentrap  bulb  is  charged  with  Nessler 
solution,  and  the  free  end  of  the  bulb  connected  with 
an  exhaustion  apparatus.  A  partial  vacuum  is  estab- 
lished gradually,  and  the  distillation  carried  on  until  200 
c.  c.  have  passed  over.  The  vacuum-tube  is  disengaged 
and  250  c.  c.  of  the  liquid  in  the  distilling  flask  drawn 


38  ANALYTIC   OPERATIONS. 

into  the  larger  upright  tube,  and  50  c.  c.  of  alkaline  per- 
manganate solution  which  has  been  previously  placed  in 
the  small  tube,  allowed  to  run  in,  after  the  flask  to  receive 
the  distillate  has  been  again  attached.  This  arrangement 
gives  50  c.  c.  of  alkaline  permanganate  acting  on  50  c.  c. 
of  water,  and  after  30  or  40  c.  c.  have  been  distilled  over 
the  water  in  the  larger  tube  is  allowed  to  drop  in  at  the 
same  rate  as  the  distillation,  which  must  not  exceed  50  c.  c. 
in  15  minutes.  This  is  continued  until  from  250  to  300 
c.  c.  have  been  distilled  over,  which  is  then  nesslerized. 
p  6  For  nesslerizing  and  other  color  comparisons, 

many  forms  of  apparatus  have  been  proposed. 
One  of  the  simplest  is  that  devised  by  Hehner, 
shown  in  Fig.  6.  It  consists  of  a  graduated 
cylinder  with  a  stopcock  near  the  base,  by 
which  the  liquid  can  be  drawn  down  at  will. 
Two  such  cylinders  may  be  used,  one  for  the 
nesslerized  distillate,  the  other  for  the  com- 
parison liquid.  The  darker  liquid  is  drawn 
out  until  the  tints  are  equal,  when  the  relative  volumes 
remaining  will  give  the  data  for  calculation. 

TOTAL  ORGANIC  NITROGEN. 

Several  processes  for  the  determination  of  the  organic 
nitrogen  in  water,  based  on  those  in  use  in  ordinary  organic 
analysis,  have  been  devised.  That  of  Frankland  and  Arm- 
strong requires  complex  and  extensive  apparatus  and  spe- 
cial skill,  has  been  shown  also  to  be  liable  to  inaccuracies, 
and  has  not  come  into  extended  use. 

The  ease  and  certainty  with  which  the  nitrogen  of  most 
organic  bodies  may  be  converted  into  ammonium  sulphate 
by  boiling  with  sulphuric  acid,  offers  a  means  of  determina- 


SANITARY    EXAMINATIONS.  .  39 

tion  free  from  the  objections  of  former  methods.  The 
method  introduced  by  Kjeldahl  for  general  organic  analy- 
sis, was  first  successfully  applied  to  water  analysis  by  Drown 
and  Martin  {Technology  Quarterly,  n,  3). 

In  their  original  process  500  c.  c.  was  concentrated  to 
about  300  c.c.,  and  the  distillate  nesslerized  for  determin- 
ing the  nitrogen  existing  as  ammonium  compounds.  The 
organic  nitrogen  is  then  determined  in  the  residual  water. 
Owing  to  the  fact  that  in  many  waters  the  organic  matter 
is  decomposed  by  boiling,  there  is  liability  to  under- 
estimation of  the  nitrogen.  It  is  best,  therefore,  to  de- 
termine at  once  the  total  unoxidized  nitrogen,  and  esti- 
mate, without  distillation,  on  a  separate  portion  of  the 
sample,  the  nitrogen  that  exists  in  ammonium  compounds. 
The  procedure  is  as  follows:  — 
Reagents  Required  :— 

Concentrated  Sulphuric  Acid. — This  should  be  as  free  as 
possible  from  nitrogen.  It  can  be  obtained  containing 
only  0.015  mgm.  in  10  c.  c. 

Sodium  Hydroxid  Solution. — The  white  granulated  caus- 
tic soda  sold  for  household  use  will  answer  ;  350  grams  are 
dissolved  in  water  and  made  up  to  1000  c.  c. 

Sodium  Carbonate  and  Hydroxid  Solution. — 25  grams  of 
each  are  dissolved  in  250  c.  c.  of  distilled  water,  and  the 
solution  boiled  down  to  200  c.  c.,  to  free  it  from  ammonium. 
Analytic  Process  :  — 

Determination  of  Nitrogen  Existing  as  Ammonium. — 200 
c.  c.  of  the  water  are  placed  in  a  stoppered  bottle,  two  c.  c. 
each  of  the  solutions  of  sodium  carbonate  and  sodium 
hydroxid  added,  the  stopper  inserted,  the  solutions  mixed 
and  allowed  to  stand  for  an  hour  or  two.  A  filter  is  pre- 
pared by  inserting  a  rather  large  plug  of  absorbent  cotton 


40  ANALYTIC   OPERATIONS. 

in  a  funnel.  This  should  be  washed  with  ammonium- 
free  water  until  the  filtrate  gives  no  color  with  Nessler 
reagent.  The  clear  portion  of  the  sample  is  drawn  off 
with  a  pipette  and  run  through  the  filter,  the  first  portions 
being  rejected,  since  it  is  diluted  by  the  water  retained 
in  the  cotton.  The  filtration  is  rapid,  and  when  100 
c.  c.  of  the  liquid  have  passed  through  it  is  nessler- 
ized.  If  but  little  ammonium  is  present,  a  narrow  tube 
about  60  centimeters  long  should  be  used  for  observing 
the  color. 

Estimation  of  the  Total  Organic  and  Ammoniac al  Nitro- 
gen.— 500  c.  c.  of  the  water  are  placed  in  a  round-bottomed 
Bohemian  glass  flask,  10  c.  c.  of  concentrated  sulphuric  acid 
added,  and  a  piece  of  pumice-stone  is  heated  to  bright  red- 
ness and  dropped  in  while  hot.  The  liquid  is  boiled  until 
the  acid  is  colorless  or  very  pale,  the  boiling  being  con- 
tinued for  nearly  an  hour  from  this  point.  The  flask  is 
then  removed  from  the  flame,  allowed  to  cool,  and  about 
250  c.  c.  of  ammonium-free  water  added.  50  c.  c.  of  the 
sodium  hydroxid  solution  should  be  placed  in  the  distil- 
ling apparatus,  Fig.  3,  about  250  c.  c.  of  water  added,  a 
piece  of  red-hot  pumice-stone  dropped  in  and  the  liquid 
distilled  until  the  distillate  is  free  from  ammonium.  It  is 
best  to  distill  until  the  retort  contains  not  more  than  100 
c.  c.  The  sulphuric  acid  solution  is  then  poured  in  slowly, 
by  means  of  a  funnel,  the  stem  of  which  touches  the  side 
of  the  retort,  so  that  the  two  liquids  do  not  mingle.  The 
stopper  of  the  retort  is  inserted,  the  liquids  mixed  by  gentle 
agitation,  and  distilled.  If  much  ammonium  is  present  it 
is  advisable  to  distill  the  first  portion  into  about  10  c.  c.  of 
very  dilute  (i  :  1000)  sulphuric  acid,  a  piece  of  glass  tube 
being  connected  to  the  condensing  worm  so  that  the  lower 


SANITARY    EXAMINATIONS.  41 

end  dips  below  the  surface  of  the  liquid.     The  distillates 
are  collected  and  nesslerized  in  the  usual  way. 

A  blank  experiment  should  be  made  to  determine  the 
amount  of  ammonium  in  the  sulphuric  acid. 

NITROGEN   AS  NITRATES. 
Solutions  Required  :— 

A.  H.  Gill  (four,  of  Amer.  Chem.  Soc.,  1894),  has 
subjected  the  various  indirect  methods  of  estimating 
nitrates  to  comparative  examination,  and  prefers  the 
following  reagents  : — 

Phenoldisulphonic  Acid. — Strong  sulphuric  acid  and  pure 
phenol  are  mixed  in  the  proportion  of  37  grams  of  the 
former  to  three  grams  of  the  latter,  and  heated  for  six 
hours  in,  not  upon,  the  water-bath.  The  resulting  com- 
pound usually  solidifies  to  a  white  mass  on  standing,  but 
can  be  easily  liquified  on  the  water-bath  during  the  evapo- 
ration of  the  samples  to  be  tested. 

Standard  Potassium  Nitrate. —  0.722  gram  of  potassium 
nitrate,  previously  heated  to  a  temperature  just  sufficient 
to  fuse  it,  are  dissolved  in  water,  and  the  solution  made  up 
to  1000  c.  c.  One  c.  c.  of  this  solution  will  contain  .0001 
grm.  of  nitrogen. 
Analytic  Process  : — 

A  measured  volume  of  the  water  is  evaporated  just  to 
dryness  in  a  porcelain  basin  about  six  cm.  in  diameter. 
One  c.  c.  of  the  phenoldisulphonic  acid  is  added  and  thor- 
oughly mixed  with  the  residue  by  means  of  a  glass  rod. 
The  liquid  is  then  diluted  with  about  25  c.  c.  of  water, 
ammonium  hydroxid  added  in  excess,  and  the  solution 
made  up  to  50  c.  c. 

The  nitrate  converts  the  phenoldisulphonic  acid  into 


42  ANALYTIC   OPERATIONS. 

picric  acid,  which  by  the  action  of  the  ammonium  hy- 
droxid  forms  ammonium  picrate ;  this  imparts  to  the 
solution  a  yellow  color,  the  intensity  of  which  is  propor- 
tional to  the  amount  present. 

One  c.  c.  of  the  standard  solution  of  potassium  nitrate 
is  now  similarly  evaporated  in  a  platinum  basin,  treated  as 
above,  and  made  up  to  50  c.  c.  The  color  produced  is 
compared  to  that  given  by  the  water,  and  one  or  the  other 
of  the  solutions  is  diluted  until  the  tints  of  the  two  agree. 
The  comparative  volumes  of  the  liquids  furnish  the  neces- 
sary data  for  determining  the  amount  of  nitrate. 

Mr.  Gill  has  furnished  me  with  an  account  of  the  method 
pursued  at  the  Massachusetts  Institute  of  Technology  for 
obtaining  a  comparison  liquid.  Ten  c.  c.  of  the  standard 
nitrate  solution  is  cautiously  evaporated,  spontaneously  or 
in  a  desiccator,  and  three  c.c.  of  the  phenoldisulphonic  acid 
added,  the  mixture  diluted  with  water  to  exactly  1000  c.  c. 
Of  this  solution,  portions  are  measured  out  with  a  finely 
and  accurately  graduated  pipette  into  the  porcelain  dish 
similar  to  that  in  which  the  water-sample  has  been  evapo- 
rated, water  added  to  make  exactly  10  c.  c.  and  then  two 
or  three  drops  of  ammonium  hydroxid  to  make  the 
liquid  alkaline.  The  quantity  of  liquid  taken  in  the  pipette 
has  the  following  values  in  parts  per  million  of  nitrogen  as 
nitrates :  10  c.  c.  =  i.o  ;  5  c.  c.  —  0.5  ;  2  c.  c.  —  0.2;  o  5 
c.  c.=  0.05.  Comparison  is  thus  made  directly  in  the  dishes. 
In  case  of  doubt  the  liquids  are  compared  in  tubes  similar 
to  nesslerizing  tubes,  but  cut  down  to  hold  15  or  20  c.  c. 

The  results  obtained  by  this  method  are  satisfactory. 
Care  should  be  taken  that  the  same  quantities  of  phenoldi- 
sulphonic acid  are  used  for  the  water  and  for  the  compari- 
son liquid. 


SANITARY    EXAMINATIONS.  43 

With  subsoil  and  other  waters  probably  containing  much 
nitrates,  10  c.  c.  will  be  sufficient;  but  with  river  and  spring 
waters,  25  c.  c.  may  be  used.  When  the  organic  matter  is 
sufficient  to  color  the  residue,  it  will  be  well  to  purify  the 
water  by  addition  of  aluminum  hydroxid  and  filtration, 
before  evaporating. 

Chlorin  interferes  with  the  accuracy  of  the  test,  but  Gill 
finds  that  when  not  amounting  to  more  than  20  parts  per 
million  it  does  not  impair  the  practical  value  of  the  results. 
When  greater  than  this,  it  is  best  to  evaporate  in  vacuo  over 
sulphuric  acid.  If  the  chlorin  be  more  than  70  parts  per 
million  it  should  be  considerably  reduced  by  the  addition 
of  silver  sulphate,  which  has  been  ascertained  to  be  free 
from  nitrates.  Nitrites  do  not  influence  the  reaction. 

The  following  is  the  process  for  determining  nitrogen  as 
nitrates  (and  nitrites)  recommended  by  the  Chemical  Sec- 
tion of  the  A.  A.  A.  S.  It  depends  upon  conversion  into 
ammonium  by  the  copper-zinc  couple,  and  subsequent 
nesslerizing.  It  is  inferior  to  the  phenoldisulphonic  acid 
method,  both  in  convenience  and  accuracy,  and  does  no1 
exclude  the  influence  of  nitrites. 

Take  two  wide-mouth  glass-stoppered  bottles,  each  hold- 
ing 250  c.  c.  and  a  piece  of  sheet  zinc  as  long  and  about  as 
wide  as  the  bottles  are  deep  from  the  shoulder  down  ;  clean 
the  zinc  by  dipping  in  dilute  acid  and  washing  with  water 
and  make  it  into  a  loose  coil  by  rolling  it  round  a  piece  of 
glass  tube.  Immerse  it  in  a  1.4  to  1.8  per  cent,  solution 
of  cupric  sulphate  in  ammonia-free  water,  and  leave  it 
there  until  its  surface  is  well  covered  with  a  continuous 
layer  of  the  black  copper;  lift  it  out  carefully,  cover  it 
in  a  beaker  with  successive  portions  of  ammonia-free 
water,  lifting  it  out  and  draining  each  time,  and  at  once 


44  ANALYTIC   OPERATIONS. 

put  it  into  one  of  the  bottles  of  acidified  water,  prepared 
as  follows  : — 

Make  500  c.  c.  of  the  water  to  be  examined  distinctly 
acid  with  oxalic  acid  added  in  fine  powder,  with  constant 
stirring,  so  that  it  shall  dissolve  readily,  and  pour  half  of 
the  liquid  into  one  of  these  250  c.  c.  bottles,  and  half  into 
the  other,  and  leave  them,  stoppered,  in  a  warm  place  for 
twenty-four  hours.  Then  nesslerize  both  samples,  decant- 
ing off  the  portions  as  wanted,  from  the  precipitated  earthy 
oxalates,  and  using  double  the  usual  quantity  of  Nessler's 
solution,  since  the  free  oxalic  acid  has  to  be  neutralized 
first  by  the  alkali  of  the  reagent.  The  proportion  of  am- 
monia may  often  be  so  large  in  the  water  in  which  the 
reduction  is  made,  by  the  copper-zinc  couple,  that  only 
five  or  ten  c.  c.  can  be  taken  for  each  test,  and  made  up 
to  50  c.  c.  by  the  addition  of  ammonia-free  water.  The 
difference  between  the  results  with  the  two  portions  of 
water,  gives  the  amount  of  nitrogen  due  to  the  oxidized 
nitrogen  compounds  in  the  water  examined. 

NITROGEN   AS  NITRITES. 

The  following  is  Ilosvay's  modification  of  Griess's  test. 
It  has  the  advantage  over  the  original  method,  that  the 
color  is  developed  more  rapidly,  and  the  solutions  are  not 
so  liable  to  change. 
Solutions  Required  : — 

Paramidobenzenesulphonic  Acid  Solution  (Sulphanilic 
Add}. — Dissolve  0.5  gram  in  150  c.  c.  of  diluted  acetic 
acid,  sp.  gr.  1.04. 

a-amidonaphthalene  Acetate  Solution. — Boil  o.i  gram  of 
solid  a-amidonaphthalene  (naphthylamin)  in  20  c.  c.  of 
water,  filter  the  solution  through  a  plug  of  washed 


SANITARY    EXAMINATIONS.  45 

absorbent  cotton,  and  mix  the  filtrate  with  180  c.  c.  of 
diluted  acetic  acid.  All  water  used  must  be  free  from 
nitrites,  and  all  vessels  must  be  rinsed  out  with  such  water 
before  tests  are  applied,  since  appreciable  quantities  of 
nitrites  may  be  taken  up  from  the  air. 

Standard  Sodium  Nitrite. — 0.275  gram  pure  silver 
nitrite  are  dissolved  in  pure  water,  and  a  dilute  solution 
of  pure  sodium  chlorid  added  until  the  precipitate  ceases 
to  form.  It  is  then  diluted  with  pure  water  to  250  c.  c., 
and  allowed  to  stand  until  clear.  For  use  10  c.  c.  of  this 
solution  are  diluted  to  100  c.  c.  It  is  to  be  kept  in  the  dark. 

One  c.  c.  of  the  dilute  solution  is  equivalent  to  .00001 
gram  nitrogen. 

The  silver  nitrite  is  prepared  thus  :  A  hot  concentrated 
solution  of  silver  nitrate  is  added  to  a  concentrated  solu- 
tion of  the  purest  sodium  or  potassium  nitrite  available, 
filtered  while  hot  and  allowed  to  cool.  The  silver  nitrite 
will  separate  in  fine  needle-like  crystals,  which  are  freed 
from  the  mother  liquor  by  filtration  by  the  aid  of  a  filter 
pump.  The  crystals  are  dissolved  in  the  smallest  possible 
quantity  of  hot  water,  allowed  to  cool  and  again  separated 
by  means  of  the  pump.  They  are  then  thoroughly  dried 
in  the  water-bath,  and  preserved  in  a  tightly-stoppered 
bottle  away  from  the  light.  The  purity  may  be  tested  by 
heating  a  weighed  quantity  to  redness  in  a  tared  porcelain 
crucible  and  noting  the  weight  of  the  metallic  silver.  154 
parts  should  leave  a  residue  of  108  parts  silver. 
Analytic  Process : — 

25  c.  c.  of  the  water  are  placed  in  one  of  the  color-com- 
parison cylinders,  and  2  c.  c.  each  of  the  test  solutions  are 
dropped  in.  It  is  convenient  to  have  a  pipette  for  each 
solution,  and  to  use  it  for  no  other  purpose. 


46  ANALYTIC   OPERATIONS. 

One  c.  c.  of  the  standard  nitrite  solution  is  placed  in 
another  clean  cylinder,  made  up  with  nitrite-free  water  to 
25  c.  c.  and  treated  with  the  reagents  as  above. 

In  the  presence  of  nitrites  a  pink  color  is  produced.  At 
the  end  of  five  minutes  the  two  solutions  are  compared, 
the  colors  equalized  by  diluting  the  darker,  and  the  calcu- 
lation made  as  explained  under  the  estimation  of  nitrates. 

The  reactions  consist  in  the  conversion  of  the  sulphan- 
ilic  acid  into  diazobenzenesulphonic  anhydrid,  by  the 
nitrite  present ;  this  compound  is  then  in  turn  converted 
by  the  amidonaphthalene  into  azo-a-amidonaphthalene- 
parazobenzene  sulphonic  acid.  The  last-named  body  gives 
the  color  to  the  liquid. 

OXYGEN-CONSUMING  POWER. 

All  organic  materials  being  more  or  less  easily  oxidized, 
several  methods  have  been  suggested  for  determining  the 
oxygen  consuming  powers  of  waters  by  treatment  with 
active  oxidizing  agents.  These  methods  are,  however, 
limited  in  value.  The  organic  matters  in  water  differ 
much  in  character  and  condition,  and  their  oxidability  is 
subject  to  much  variation,  according  to  the  circumstances 
under  which  the  test  is  made.  Nevertheless,  as  a  high 
oxygen-consuming  power  certainly  indicates  departure  from 
purity,  some  additional  evidence  may  be  obtained.  Potas- 
sium permanganate  is  especially  suitable.  The  test  is 
usually  made  by  introducing  a  known  amount  of  the  per- 
manganate into  the  water,  which  has  been  rendered  acid, 
and  measuring  after  a  definite  period  the  proportion  which 
has  been  decomposed. 

It  must  not  be  overlooked  that  if  a  water  contains 
nitrites,  ferrous  compounds,  or  sulphur  compounds  other 


SANITARY    EXAMINATIONS.  47 

than  sulphates,  the  proportion  of  oxygen  consumed  will  be 
greater  than  that  required  for  the  organic  matter.  It  has 
been  proposed,  in  order  to  remove  the  nitrites  before 
applying  the  permanganate,  to  take  500  c.  c.  of  the  water, 
add  10  c.  c.  of  the  dilute  sulphuric  acid,  boil  for  twenty 
minutes,  allow  to  cool,  and  then  treat  with  permanganate. 
Since,  however,  the  amount  of  nitrites,  if  appreciable,  can 
be  directly  determined,  it  is  more  satisfactory  to  deduct 
from  the  oxygen  consumed  the  amount  required  to  con- 
vert the  nitrites  present  into  nitrates,  and  the  remainder 
will  be  that  required  for  the  other  oxidizable  ingredients. 
14  parts  of  nitrogen  existing  as  nitrite  require  16  parts  of 
oxygen  for  conversion  into  nitrate.  Similarly,  112  parts 
of  iron  in  a  ferrous  compound  will  require  16  parts  of 
oxygen  for  conversion  to  the  ferric  condition. 

Of  the  following  methods  the  first  is  due  in  the  main  to 
Dr.  Tidy,  has  been  improved  by  Dr.  Dupre,  and  is  ap- 
proved by  the  Society  of  Public  Analysts  of  Great  Britain  : — 
Solutions  Required : — 

Standard  Permanganate. — .395  gram  pure  potassium  per- 
manganate are  dissolved  in  distilled  water,  and  the  solution 
made  up  to  1000  c.  c.  One  c.  c.  is  equal  to  .0001  gram 
oxygen. 

Diluted  Sulphuric  Acid. — Add  50  c.  c.  of  pure  sulphuric 
acid  to  100  c.  c.  of  water,  and  then  add  solution  of  potas- 
sium permanganate  until  a  faint  pink  color  is  obtained, 
which  is  permanent  when  the  liquid  is  heated  to  80° 
Fahrenheit  for  four  hours. 

Potassium  lodid. — 10  grams  of  the  pure  salt  recrystallized 
from  alcohol  are  dissolved  in  100  c.  c.  of  distilled  water. 

Sodium  Thiosulphate. — One  gram  of  the  pure  crystallized 
salt  dissolved  in  2000  c.  c.  of  distilled  water. 


48  ANALYTIC   OPERATIONS. 

Starch  Indicator. — One  gram  of  clean  starch  is  mixed 
smoothly  with  cold  water  into  a  thin  paste,  then  poured 
gradually  into  about  200  c  c.  of  boiling  water,  the  boiling 
continued  for  one  minute,  the  liquid  allowed  to  settle,  and 
the  clear  portion  used.  It  is  best  freshly  prepared. 
Analytic  Process  : — 

Two  determinations  are  made,  one,  of  the  oxygen  con- 
sumed in  fifteen  minutes,  which  is  considered  to  represent 
the  nitrites,  sulphids,  or  ferrous  compounds,  and  the  other 
of  the  oxygen  consumed  by  four  hours'  action.  Both  de- 
terminations are  made  at  a  temperature  of  80°  F.  Three 
glass  stoppered  bottles,  of  about  350  c.  c.  capacity,  are 
rinsed  with  strong  sulphuric  acid,  and  then  with  water.  In 
one  is  placed  250  c.  c.  of  pure  distilled  water  as  a  control 
experiment,  and  in  each  of  the  others  250  c.  c.  of  the  water 
to  be  tested.  The  bottles  are  stoppered  and  brought  to  a 
temperature  of  80°  F.;  10  c.  c.  of  the  dilute  sulphuric  acid 
and  10  c.  c.  of  the  standard  permanganate  are  added  to 
each  and  the  stoppers  again  replaced.  At  the  end  of 
fifteen  minutes  one  sample  of  water  is  removed  from  the 
bath,  and  two  or  three  drops  of  the  potassium  iodid  solu- 
tion added  to  remove  the  pink  color.  After  thorough 
admixture,  the  thiosulphate  solution  is  run  in  from  a  burette 
until  the  yellow  color  is  nearly  destroyed,  a  few  drops  of 
the  starch  solution  added,  and  the  addition  of  the  thiosul- 
phate continued  until  the  blue  color  is  quite  discharged. 
If  the  addition  of  the  thiosulphate  solution  has  been 
properly  conducted,  one  drop  of  the  permanganate  solu- 
tion will  restore  the  blue  color. 

The  other  bottles  are  maintained  at  8o°F.  for  four  hours. 
Should  the  pink  color  disappear  rapidly  in  the  bottle  con- 
taining the  water  under  examination,  10  c.  c.  of  the  per- 


SANITARY    EXAMINATIONS.  49 

manganate  solution  must  be  added  to  each  bottle,  in  order 
to  maintain  a  distinct  pink  color.  At  the  end  of  four  hours 
each  bottle  is  removed  from  the  bath,  two  or  three  drops 
of  potassium  iodid  added,  and  the  titration  with  thiosul- 
phate  solution  conducted  as  just  described.  The  calcu- 
lation is  most  conveniently  made  as  follows: — 

a  =.  number  of  c.  c.  required  for  the  control  experiment. 

b  =  number  of  c.  c.  required  for  the  water  under  exami- 
nation. 

c  =  available  O  in  permanganate  (.001  for  10  c.  c.). 

x  —  oxygen  consumed  by  water. 

Then,  a  :  a—b  :  :  c  :  x. 

The  following  method  is  recommended  by  the  Chemical 
Section  of  the  American  Association  for  the  Advancement 
of  Science  :— 

''Prepare  a  solution  of  potassium  permanganate  contain- 
ing o.i  mgm.  of  available  oxygen  to  one  c.  c.  and  a  solu- 
tion of  oxalic  acid  of  such  strength  as  to  decompose  the 
permanganate  solution,  volume  for  volume,  the  strength 
being  re-determined  from  time  to  time.  The  water  used 
for  making  these  solutions  should  be  purified  by  distillation 
from  alkaline  permanganate. 

"  To  200  c.  c.  of  water  to  be  examined,  in  a  400  c.  c. 
flask,  add  10  c.  c.  of  dilute  sulphuric  acid  (i  :  3)  and  such 
measured  quantity  of  the  permanganate  as  will  give  a  per- 
sistent color;  boil  ten  minutes,  add,  if  necessary,  more 
permanganate  in  measured  quantities  so  as  to  maintain  the 
red  color;  remove  the  flask  from  the  lamp,  add  10  c.  c.  of 
oxalic  acid  solution  to  destroy  the  color,  or  more  if 
required  by  the  excess  of  permanganate,  and  then  add  per- 
manganate, drop  by  drop,  till  a  faint  pink  tint  appears. 


50  ANALYTIC   OPERATIONS. 

From  the  total  quantity  of  permanganate  used  deduct  the 
equivalent  of  the  oxalic  acid  used,  and  from  the  remainder 
calculate  the  milligrams  of  oxygen  consumed  by  the  oxid- 
izable  organic  matter  in  the  water." 

The  oxygen-consuming  power  may  also  be  indirectly 
estimated  by  the  action  of  the  organic  matter  upon  silver 
compounds.  H.  Fleck's  method  {Fresenius1  Quantitative 
Analysis,  English  edition),  depends  upon  the  reduction 
produced  by  boiling  the  water  with  alkaline  solution  of 
silver  thiosulphate  and  estimation  of  the  unreduced  silver. 
A.  R.  Leeds  (Land.,  Edin.  and  Dub,  Phil.  Mag.,  July, 
1883)  gives  a  method  by  treating  the  water  with  decinormal 
silver  nitrate,  exposing  to  light  until  it  settles  perfectly 
clear,  and  estimating  the  reduced  silver  in  the  deposit. 

These  methods  are  open  to  practically  the  same  objections 
as  in  the  use  of  permanganate,  and  do  not  seem  to  possess 
any  decided  advantage.  Qualitative  results  of  some 
interest  may  occasionally  be  obtained  by  the  following 
method:  Twoc.c.  of  a  one  per  cent. solution  of  silver  nitrate, 
rendered  decidedly  alkaline  by  ammonium  hydroxid,  are 
added  to  100  c.  c.  of  the  water  in  a  stoppered  bottle,  which 
is  then  placed  in  full  sunlight  for  two  hours.  Waters  con- 
taining but  little  organic  matter  will  not  show  at  the  end  of 
this  period  any  appreciable  tint.  The  following  results 
will  show  the  character  of  the  test : — 

Schuylkill  water,  ....        no  color. 

"  "     with  0.02  c.  c.  urine,    .    .  red-brown. 

"  "     with  o.oi  c.  c.  urine,    .    .  deep  brown. 

"  "     with  0.25  gram  raw  sugar,  no  color. 

Well  water,  not  perfectly  pure,  but 

not  unfit  to  drink,     ....  faint  black. 
"         "      markedly  contaminated,     .    .  black  ppt.  almost 

immediately. 
Water  from  a  small  stream  quite  pure,  .    .  no  color. 


SANITARY    EXAMINATIONS.  51 

PHOSPHATES. 

Solutions  Required : — 

Ammonium  Molybdate. — Ten  grams  of  molybdic  anhy- 
drid  are  dissolved  in  41.7  c.  c.  of  ammonium  hydroxid,  sp. 
gr.  0.96,  and  the  solution  is  poured  slowly,  and  with  con- 
stant stirring,  into  125  c.  c.  of  nitric  acid,  sp.  gr.  1.20, 
and  allowed  to  stand  in  a  warm  place  for  several  days, 
until  clear. 
Analytic  Process  : — 

500  c.  c.  of  the  water  are  slightly  acidified  with  nitric 
acid,  and  evaporated  to  about  50  c.  c.  A  few  drops  of 
dilute  solution  of  ferric  chlorid  are  added  and  then 
ammonium  hydroxid  in  slight  excess.  The  precipitate, 
which  contains  all  the  phosphate,  is  filtered  off  and 
dissolved  on  the  filter  by  the  smallest  possible  quantity  of 
hot  dilute  nitric  acid.  The  filtrate  and  washings  should 
not  exceed  five  c.  c. ;  if  more,  they  must  be  evaporated  to 
this  bulk.  The  liquid  is  heated  nearly  to  boiling,  two  c.  c. 
of  ammonium  molybdate  solution  added,  and  the  liquid 
kept  moderately  warm  for  half  an  hour.  If  the  quantity 
of  precipitate  is  appreciable,  it  is  collected  on  a  small 
weighed  filter,  washed  with  distilled  water,  dried  at  100° 
F.  and  weighed.  The  weight  of  the  precipitate  multiplied 
by  °-°5  gives  the  amount  of  Pd.  If  the  quantity  is  not 
sufficient  to  collect  in  this  manner,  it  is  usually  reported, 
according  to  circumstances,  as  "  traces,"  "  heavy  traces," 
or  "very  heavy  traces." 

DISSOLVED  OXYGEN. 

The  method  here  given,  a  modification  of  Mohr's,  was 
proposed  by  Blarez.  It  is  rapid  and  satisfactory. 


5 2 


ANALYTIC    OPERATIONS. 


Solutions  Required : — 

Sodium  Hydroxid. — 40  grams  of  pure  sodium  hydroxid 
to  the  liter. 

Ferrous- Ammonium  Sulphate. — 40  grams  dissolved  in 
about  a  liter  of  water,  and  acidified  with  a  few  drops  of 
concentrated  sulphuric  acid. 

Decinormal  Potassium  Permanganate. — -3.156  grams 
dissolved  in  a  liter  of  distilled  water.  The  accuracy  of 
this  solution  should  be  determined  by  titration  with  a 
known  weight  of  ferrous-ammonium  sulphate.  One  c.  c. 
should  be  equivalent  to  .0392  grm.  ferrous-ammonium 
sulphate  (.0008  gram  of  oxygen). 

The  apparatus  employed  (shown  in  Fig.  7)  is  a  globular 
separator,  of  about  250  c.  c.  capacity.     Above  the  bulb  is 
a  caoutchouc  stopper  carrying  a  cylindrical  funnel,  of  about 
12  c.  c.  capacity,  terminating  in  a  tube,  8  mm.  calibre, 
sharply  contracted  at  the  outlet  to  a  capillary 
opening.    The  tube  should  project  about  6  mm. 
below  the  stopper.     The  exact  capacity  of  the 
apparatus  is  measured  as  follows  :     The  bulb  is 
completely  filled  with  water  and  the  stopper 
inserted ;  the  level  of  the  water  will  rise  slightly 
in  the  funnel  tube,  and  should  be  brought  down 
to  its  outlet  by  drawing  a  little  off  at  the  stop- 
cock,  after   which  the   water    is   run    into  a 
graduated  measure  and  its  volume  noted. 
Analytic  Process  :— 

35  c.  c.  of  mercury  and  10  c.  c.  of  sodium 
hydroxid  solution  are  put  into  the  bulb,  and 
then   sufficient   of  the   water  to  be  tested  to 
fill  it.     The   funnel   stopper   is   inserted   and    the   water 
which   rises    into   the   funnel  brought  into  the  bulb  by 


FIG.  7. 


SANITARY    EXAMINATIONS.  53 

cautiously  running  out  at  the  stopcock,  mercury,  the 
volume  of  which  should  be  noted.  The  exact  volume  of 
water  used  is  thus  known.  Five  c.  c.  of  the  ferrous- 
ammonium  sulphate  solution  are  poured  into  the  funnel, 
brought  into  the  bulb  by  running  out  mercury,  and  the 
liquid  thoroughly  mixed  by  giving  the  apparatus  a  gyratory 
movement.  After  standing  five  or  six  minutes  the  oxygen 
will  be  completely  absorbed  ;  10  c.  c.  of  the  diluted  sul- 
phuric acid  are  now  added  by  the  same  method.  On 
agitating  the  bujb  the  contents  become  clear.  The  watery 
liquid  is  then  transferred  to  a  beaker  and  titrated  with 
decinormal  permanganate.  A  volume  of  water  equal  to 
that  used  in  the  test  is  poured  into  another  beaker,  10  c.  c. 
each  of  the  sodium  hydroxid  and  diluted  sulphuric  acid 
added,  and  then  five  c.  c.  of  ferrous-ammonium  sulphate 
solution.  The  resulting  liquid  is  titrated  with  permanga- 
nate. The  weight  of  oxygen  corresponding  to  the 
difference  between  the  two  titrations  gives  the  weight  of 
dissolved  oxygen  in  the  liquid  employed.  From  this 
should  be  subtracted  as  correction  the  amount  of  oxygen 
dissolved  by  a  volume  of  water  equal  to  that  of  the  sodium 
hydroxid  solution  used.  This  is  found  by  reference  to 
the  table  in  the  appendix.  The  amount  of  oxygen  dis- 
solved in  the  sulphuric  acid  has  no  appreciable  effect. 

Nitrates  do  not  appear  to  impair  the  accuracy  of  this 
method,  and  the  interfering  action  of  nitrites  and  other 
reducing  compounds  is  avoided  by  the  control  experiment 
as  detailed. 

It  is  perhaps  hardly  necessary  to  add  that  the  exact  tem- 
perature of  the  water  is  to  be  noted  at  the  time  of  collec- 
tion of  the  sample. 

In  transferring  to  the  bulb,  the  water  should  be  agitated 


54  ANALYTIC   OPERATIONS. 

as  little  as  possible  in  contact  with  the  air,  in  order  to 
avoid  the  absorption  of  oxygen.  A  siphon  should  be  used 
for  this  purpose,  the  lower  end  being  allowed  to  reach  to 
the  bottom  of  the  bulb. 

The  following  modification  is  suggested  as  being  especi- 
ally suitable  for  poorly  oxygenated  waters:  An  accu- 
rately stoppered  bottle,  the  exact  capacity  of  which  is 
known  (about  500  c.  c.  is  a  convenient  size),  is  completely 
filled  at  the  source  with  the  water  to  be  examined,  and  the 
stopper  inserted  so  as  to  drive  out  all  air.  The  stopper  is 
removed  in  the  laboratory,  50  c.  c.  of  the  water  drawn  off 
with  a  pipette,  and  the  water  covered  immediately  with  a 
layer  of  gasoline  previously  purified  by  shaking  up  several 
times  with  a  solution  of  potassium  permanganate  and  di- 
luted sulphuric  acid,  and  washed  several  times  with  water. 
The  sodium  hydroxid,  ferrous-ammonium  sulphate,  and 
sulphuric  acid  are  introduced  into  the  water  by  means  of 
burettes  to  which  long  glass  delivery  tubes  are  attached. 
The  titration  with  potassium  permanganate  is  conducted 
in  the  same  way.  The  liquid  is  mixed  from  time  to  time, 
as  the  solutions  are  added,  by  means  of  a  glass  rod.  In 
this  way  the  air  may  be  completely  excluded  throughout 
the  entire  operation.  The  amount  of  water  titrated  is,  of 
course,  equal  to  the  whole  capacity  of  the  bottle,  less  the 
50  c.  c.  removed  by  the  pipette. 

The  control  experiment  on  an  equal  volume  of  the  water, 
and  the  correction  for  the  oxygen  added  with  the  sodium 
hydroxid  solution,  are  made  as  detailed  above. 

Dupre  has  employed  the  determination  of  free  oxygen 
for  the  estimation  of  the  proportion  of  oxygen-consuming 
microbes.  The  principle  of  the  method  is  that  pure  water, 
if  kept  in  a  closed  bottle,  will  neither  gain  nor  lose  oxygen 


SANITARY    EXAMINATIONS.  55 

in  any  length  of  time,  but  if  organisms  capable  of  causing 
absorption  of  oxygen  are  present,  the  quantity  will  de- 
crease. 

The  experiment  is  carried  out  by  placing  a  sample  of 
the  water  in  a  clean  bottle,  and  vigorously  shaking  it  to 
saturate  with  air.  A  clean  250  c.  c.  bottle  is  completely 
filled  with  the  water,  tightly  stoppered,  and  maintained  at 
a  temperature  of  68°  F.  for  ten  days ;  the  free  oxygen  re- 
maining is  then  determined. 

POISONOUS   METALS. 

Under  this  conventional  title  are  included  barium, 
chromium,  zinc,  arsenum,  copper,  and  lead ;  manganese,  iron, 
aluminum  also,  though  not  usually  classed  in  this  group, 
are  objectionable  when  present  in  notable  amounts. 

Barium  is  rarely  present,  and  only  in  water  containing 
no  sulphates.  It  can  be  detected  and  estimated  by  slightly 
acidifying  the  water  with  hydrochloric  acid,  filtering  if 
necessary,  and  adding  solution  of  calcium  sulphate.  The 
precipitated  barium  sulphate  is  collected  and  weighed  in 
the  usual  way. 

Chromium  is  rarely  present,  but  may  be  looked  for  in 
the  waste  waters  of  dye  works  and  similar  sources.  To 
detect  it,  a  considerable  volume  of  the  water  is  evaporated 
to  dryness  with  addition  of  a  small  amount  of  potassium 
chlorate  and  nitrate,  transferred  to  a  porcelain  crucible  and 
brought  to  quiet  fusion  ;  any  chromium  present  will  be 
found  in  the  residue  in  the  form  of  chromate.  The  fused 
mass,  after  cooling,  is  boiled  with  a  little  water,  filtered, 
the  filtrate  rendered  slightly  acid  with  hydrochloric  acid, 
and  a  solution  of  hydrogen  dioxid  added.  In  the  pres- 
ence of  chromium  a  transient  blue  color  will  appear;  by 


56  ANALYTIC   OPERATIONS. 

adding  a  little  ether,  and  shaking  the  mixture  the  color 
will  pass  into  the  ether,  and  on  standing  will  form  a  blue 
layer  on  the  surface  of  the  water. 

Zinc  is  best  detected  by  the  test  described  by  Allen. 
The  water  is  rendered  slightly  alkaline  by  addition  of 
ammonium  hydroxid,  heated  to  boiling,  filtered,  and  the 
clear  liquid  treated  with  a  few  drops  of  potassium  ferro- 
cyanid ;  in  the  presence  even  of  the  merest  trace  of  zinc 
a  white  precipitate  will  be  produced. 

Arsenum  is  most  readily  detected  by  Reinsch's  test. 
One  liter  of  the  water  is  rendered  slightly  alkaline  by  pure 
sodium  carbonate,  and  evaporated  nearly  to  dryness  in  a 
porcelain  basin.  Two  or  three  c.  c.  of  water  strongly  acidu- 
lated with  hydrochloric  acid  are  placed  in  a  small  test-tube, 
about  y^  square  centimeter  of  bright  copper  foil  is  added, 
and  the  liquid  boiled  gently  for  a  few  moments.  If  the 
copper  remains  bright,  showing  that  the  reagents  contain 
no  arsenum,  the  water-residue  is  acidified  with  hydrochloric 
acid,  added  to  the  contents  of  the  test-tube,  and  the  liquid 
again  boiled  for  several  minutes.  If  arsenum  be  present, 
a  steel-gray  stain  will  appear  on  the  copper.  The  slip  is 
removed,  washed  with  distilled  water,  thoroughly  dried  by 
pressure  between  filter  paper,  inserted  into  a  narrow  glass 
tube  closed  at  one  end,  which  has  been  previously  dried  by 
heating  nearly  to  redness.  The  tube  is  gently  heated  at 
the  point  at  which  the  copper  rests ;  the  deposit  will 
sublime  and  collect  on  the  cooler  portion  of  the  tube,  in 
crystals  which  the  microscope  shows  to  be  octahedral. 

Since  small  amounts  of  arsenum  frequently  occur  in 
reagents  and  in  glass  vessels,  care  must  be  taken  to  avoid 
such  sources  of  error.  Sodium  carbonate  solution  may 
contain  arsenum  dissolved  from  the  glass  bottle  in  which 


SANITARY    EXAMINATIONS.  57 

it  is  kept.  It  is  best,  therefore,  to  use  the  solid  carbonate 
for  rendering  the  water  alkaline,  and  to  determine  its 
purity  before  use. 

Iron  is  detected  by  the  addition  of  a  drop  of  ammonium 
sulphid  to  the  water  in  a  tall  glass  cylinder.  Ferrous  sul- 
phid  is  formed,  having  a  greenish-black  color,  instantly 
discharged  by  acidifying  the  water  with  dilute  hydrochloric 
acid.  A  still  better  test  is  the  production  of  a  blood-red 
color,  with  potassium  thiocyanate,  due  to  the  formation 
of  ferric  thiocyanate.  The  water  should  be  first  boiled 
with  a  few  drops  of  nitric  acid,  to  convert  the  iron  to  the 
ferric  condition,  cooled,  and  a  drop  or  two  of  the  solution 
of  potassium  thiocyanate  added.  The  test  is  very  deli- 
cate. Either  of  the  above  tests  may  be  made  quantitative 
by  matching  the  color  produced  in  100  c.  c.  of  the  water 
with  that  obtained  from  a  known  weight  of  iron.  The 
method  with  potassium  thiocyanate  is  preferable,  as  it  is 
more  delicate  and  there  are  fewer  interfering  conditions. 
The  following  is  the  method  as  elaborated  by  Thompson 
and  described  in  Button's  "Volumetric  Analysis:  " — 
Solutions  Required  :— 

Standard  Ferric  Sulphate. — o.  7  gram  ferrous  ammonium 
sulphate  are  dissolved  in  water  acidified  with  sulphuric 
acid,  and  potassium  permanganate  solution  added  until  the 
solution  turns  a  very  faint  pink  color.  The  solution  is 
diluted  to  a  liter.  One  c.  c.  contains  o.  i  milligram  iron. 

Diluted  Nitric  Acid. — 30  c.  c.  concentrated  nitric  acid 
diluted  with  water  to  about  100  c.  c. 

Potassium  Thiocyanate. — Five  grams  of  the  salt  dissolved 
in  about  100  c.  c.  water. 
Analytic  Process : — 

About  100  c.  c.  of  the  water  are  evaporated  to  small  bulk, 


58  ANALYTIC   OPERATIONS. 

acidified  with  hydrochloric  acid,  and  just  sufficient  dilute 
potassium  permanganate  solution  added  to  convert  all  the 
iron  to  the  ferric  condition.  The  liquid  is  evaporated 
nearly  to  dryness  to  drive  off  excess  of  acid,  then  diluted 
to  its  original  volume,  100  c.  c.  In  two  tall  glasses 
marked  at  100  c.  c.,  five  c.  c.  of  the  nitric  acid  and  15 
c.  c.  of  the  thiocyanate  solution  are  placed.  To  one  of 
these  a  measured  volume  of  the  treated  water  is  added  and 
both  vessels  filled  up  to  the  mark  with  distilled  water.  If 
iron  is  present,  a  blood-red  color  will  be  produced.  Stand- 
ard iron  solution  is  added  to  the  second  vessel  until  the  color 
agrees.  The  amount  of  water  which  is  added  to  the  first 
glass  will  depend  upon  the  quantity  of  iron  it  contains ; 
not  more  should  be  used  than  will  require  two  or  three  c.  c. 
of  the  standard  to  match  it,  otherwise  the  color  will  be  too 
deep  for  comparison. 

Manganese. — The  following  method  is  described  by 
Wanklyn  in  his  treatise  on  water-analysis.  About  one  liter 
of  the  water  is  evaporated  to  small  bulk,  nearly  neutralized 
by  hydrochloric  acid  and  treated  with  a  few  drops  of  a 
solution  of  hydrogen  dioxid.  The  formation  of  a  brown 
precipitate  indicates  the  presence  of  manganese.  The  test 
is  very  delicate.  The  precipitate  may  be  collected  on 
a  filter,  the  filter  ashed,  and  the  residue  fused  with  a  mix- 
ture of  sodium  carbonate  and  potassium  nitrate.  Green 
potassium  manganate  will  be  produced,  which,  when  boiled 
with  water,  will  give  a  bright  red  solution  of  potassium 
permanganate.  The  quantitative  determination  is  given 
elsewhere. 

Aluminum. — Traces  of  this  element  are  to  be  ex- 
pected in  all  waters,  and  it  is  not  usual  to  test  for  it  except 
in  elaborate  analysis  of  the  mineral  ingredients,  as  de- 


SANITARY    EXAMINATIONS.  59 

scribed  in  another  section.  The  use  of  aluminum  sulphate 
as  a  coagulant  in  many  rapid-filtration  methods  makes  it 
necessary  to  examine  effluents  for  excess  of  precipitant,  and 
this  may  be  done  by  the  following  method  devised  by  Mrs. 
Richards : — 

To  25  c.  c.  of  the  water  to  be  tested  (concentrated  from 
one  liter  or  more,  if  necessary)  is  added  a  few  drops  of 
freshly  prepared  logwood  decoction  ;  any  alkali  is  neutra- 
lized and  the  color  is  brightened  by  the  addition  of  two 
or  three  drops  of  acetic  acid.  By  comparison  with 
standard  solutions,  the  amount  of  alum  present  may  be 
determined.  One  part  of  alum  in  1,000,000  of  water  can 
be  detected  with  certainty.  In  cases  of  greater  dilution 
concentration  of  several  liters  may  be  necessary  to  obtain 
a  decisive  test.  The  logwood  chips  yield  the  right  color 
only  after  having  been  treated  with  boiling  water  two  or 
three  times,  rejecting  the  successive  decoctions.  The  first 
portion  gives  a  yellow  color,  the  third  or  fourth  usually 
a  deep  red. 

Lead  may  be  readily  detected  by  adding  to  the  water  in 
a  tall  glass  cylinder  a  drop  of  ammonium  sulphid ;  brown- 
ish black  lead  sulphid  is  formed,  which  does  not  dissolve 
either  by  acidulating  the  water  with  dilute  hydrochloric 
acid  (distinction  from  iron),  nor  by  the  addition  of  about 
one  c.  c.  of  a  strong  solution  of  potassium  cyanid  (dis- 
tinction from  copper).  S.  Harvey  {Analyst,  April,  1890) 
gives  the  following  method  for  detecting  lead  in  water : 
250  c.  c.  are  placed  in  a  conical  precipitating  jar,  about 
o.i  gram  of  crystallized  potassium  dichromate  is  added 
and  dissolved  by  agitation.  The  same  volume  of  lead-free 
water  is  treated  in  the  same  manner,  and  the  two  solutions 
placed  side  by  side.  Water  containing  0.3  parts  per  mil- 


60  ANALYTIC   OPERATIONS. 

lion,  will  show  a  turbidity  in  15  minutes  which  will  be 
rendered  more  distinct  by  contrast  with  the  clear  water 
alongside.  By  allowing  the  jar  to  stand  for  about  twelve 
hours  undisturbed,  the  precipitate  will  settle  and  will  be- 
come still  more  distinct.  No  other  metal  likely  to  be  pres- 
ent in  water  will  give  a  similar  reaction. 

In  the  absence  of  copper  the  amount  of  lead  present 
may  be  determined  as  follows :  A  solution  is  prepared  con- 
taining 1.6  grams  of  lead  nitrate  to  the  liter;  one  c.  c.  of 
this  contains  one  milligram  lead.  100  c.  c.  of  the  water  to 
be  tested  are  placed  in  a  tall  glass  vessel,  made  acid  by  the 
addition  of  a  few  drops  of  acetic  acid  and  five  c.  c.  of 
hydrogen  sulphid  added.  In  a  similar  vessel  100  c.  c.  of 
distilled  water  are  placed,  together  with  the  same  quantities 
of  acetic  acid  and  hydrogen  sulphid,  and  sufficient  of  the 
standard  lead  solution  to  match  the  tint  in  the  'first  cylin- 
der. The  amount  of  lead  in  the  water  under  examination 
is  thus  known. 

Copper  is  detected  in  the  same  manner  as  lead  by 
acidifying  the  water  with  acetic  acid  and  adding  hydrogen 
sulphid.  The  precipitate  is  distinguished  from  lead 
sulphid  by  the  fact  that  the  color  is  discharged  on  the 
addition  of  about  one  c.  c.  of  a  strong  solution  of  pure 
potassium  cyanid.  It  may  be  further  confirmed  by  the 
addition  to  another  portion  of  the  water  of  a  solution  of 
potassium  ferrocyanid.  In  the  presence  of  even  a  very 
small  amount  of  copper,  a  mahogany  red  color  is  pro- 
duced. 

In  the  absence  of  lead,  copper  is  estimated  in  the  same 
way  as  that  metal,  using,  however,  a  standard  solution  of 
copper  for  the  comparison  liquid.  This  is  made  by  dis- 
solving 3.929  grams  of  crystallized  copper  sulphate  in  one 


SANITARY    EXAMINATIONS. 


6l 


liter  of  water.  One  c.  c.  of  the  solution  contains  one 
milligram  copper. 

If  both  lead  and  copper  are  present,  a  large  quantity  of 
the  water  should  be  evaporated  to  small  bulk,  and  the 
metals  separated  and  estimated  by  any  one  of  the  ordinary 
laboratory  methods. 

The  following  table,  prepared  by  A.  J.  Cooper,  indicates 
the  comparative  delicacy  of  some  of  the  ordinary  tests  for 
the  detection  of  poisonous  metals  in  water : — 


Depth  of  Liquid,  14^  inches. 

Metal. 

Reagent. 

Depth  of  Liquid,  3^  inches. 

Cylinder  enclosed  in  opaque 
tube. 

i  pa  t  of  metal  detected  in 

i  part  of  metal  detected  in 

Copper,  .    . 

K4Cy6Fe 
ls'H4HO 

,000,000  of  water. 
,000,000        " 

11,750,000  of  water. 
1,950,000        ' 

Zinc,    .   !    '. 
Arsenic,  .    . 

H2S 
NH4HS 
H2S 

,150,000        " 
,500,000        " 
3,600,000 

15,660,000 
7,520,000        ' 

Lead,  .    . 

K2Cr04 

4  ,000,000 

5,875,000 

H2S 

100,000,000 

196,000,000 

BIOLOGIC  EXAMINATIONS. 

In  a  comprehensive  sense  the  living  organisms  of  water 
include  representatives  of  all  the  great  groups  of  animals 
and  plants.  The  presence  of  any  of  the  higher  orders  of 
organic  forms  may  be  taken  as  an  indication  of  moderate 
purity,  as  these  are  absent  from  very  foul  water.  From  an 
analytic  point  of  view,  observation  is  limited  to  the  deter- 
minations of  those  forms  which  are  inappreciable  to  the 
unassisted  eye.  As  far  as  regards  some  of  the  moderately 
complex  organisms,  such  as  the  minute  crustaceans,  algae, 
desmids,  and  even  the  amebae,  it  may  be  said  that  while 
some  general  inferences  as  to  the  character  and  history  of 


62  ANALYTIC   OPERATIONS. 

the  water  may  be  deduced  from  an  identification  of  the 
specific  forms,  no  definite  sanitary  signification  can  be 
attached  to  them.  The  ova  of  the  entozoa  might  in  some 
cases  be  detected  by  careful  search,  and  would  indicate 
recent  pollution  of  a  highly  dangerous  character. 

Cohn  {Beitr.  z.  Biol.  d.  Pflanz.*)  regards  chlorophyl- 
producing  plants  (diatoms  and  green  algae),  together  with 
the  infusoria  that  feed  upon  them,  and  species  of  entomos- 
traca  (Daphnia  and  Cyclops),  when  present  in  only  moder- 
ate amounts,  as  indicating  water  not  very  rich  in  dissolved 
organic  matter.  Species  of  Cladothrix,  Crenothrix  and 
Beggiatoa,  which  are  among  the  larger  bacteria,  and  fre- 
quently appear  as  branching  forms,  indicate  suspended 
organic  matter  ;  while  dissolved  organic  matter  in  a  state 
of  active  decomposition  is  indicated  by  the  presence  of 
ordinary  bacteria  {Bacilli,.  Spirilla),  etc. 

Cladothrix  dichotoma  withdraws  iron  from  water,  and 
fixes  it,  causing  obstructions  in  iron  water  pipes.  Creno- 
thrix Kiihniana  Rabenhorst,  is  seen  in  water  containing 
iron  and  sometimes  causes  a  disagreeable  odor. 

The  number  of  the  higher  forms  present  in  any  sample 
will  depend  very  much  upon  the  point  at  which  it  is  col- 
lected, they  being  more  numerous  in  the  neighborhood  of 
large  plants  and  at  the  bottom  and  sides  of  streams. 
Under  our  present  knowledge,  no  pathogenic  power  can 
be  assigned  to  the  higher  forms  of  organic  life,  except 
entozoa,  but  their  bodies  after  death  may  indirectly  con- 
tribute to  the  rapid  increase  of  the  bacilli  proper,  by  serving 
as  food. 

Several  observers,  notably  Sedgwick  and  Rafter,  have 
paid  considerable  attention  to  the  recognition  of  the  ani- 
mal and  vegetable  forms  in  surface-waters.  Some  of  these 


SANITARY    EXAMINATIONS.  63 

forms,  while  not  apparently  directly  disease-producing, 
cause  disagreeable  odors  and  colors  in  water;  in  the 
warm  season  of  the  year  when  these  waters  are  stored  in 
reservoirs,  considerable  annoyance  is  felt  by  the  users,  and 
the  engineer-in-charge  is  subjected  to  much  criticism. 
For  some  years  the  American  Water- works  Association  has 
had  a  special  committee  engaged  in  collecting  data  bearing 
upon  this  point,  and  devising  methods  for  preventing  the 
conditions.  No  satisfactory  explanation  or  remedy  has 
yet  been  offered  by  this  committee,  but  it  has  been  found 
that  even  crude  filtration-methods,  such  as  allowing  the 
water  to  pass  through  a  dike  of  porous  soil  before  storing 
it  in  a  reservoir,  will  diminish  the  tendency  to  these  con- 
ditions. Cleansing  a  reservoir,  disinfecting  the  inner  sur- 
face, for  instance,  by  whitewashing,  has  also  improved  the 
condition.  (See  Addenda,  p.  136.) 

A  summary  of  Sedgwick's  method,  with  some  modifica- 
tions by  Dr.  Williston,  is  given  by  the  latter  in  a  Report 
on  Connecticut  water-supplies  for  1889-90. 

In  ordinary  cases  about  100  c.c.  are  employed.  Some- 
times it  will  be  advantageous  to  use  double  this  quantity, 
at  other  times  much  less.  In  rare  cases  the  examination 
can  be  made  upon  unfiltered  water.  Originally  sand  was 
employed  for  a  filter  material,  but  Williston  finds  that 
precipitated  silica  made  by  decomposing  silicon  fluorid 
with  water  is  more  satisfactory.  This  precipitated  silica  is 
a  commercial  article,  and  its  method  of  preparation  is 
given  in  all  the  larger  manuals  of  chemistry. 

A  small  glass  funnel  with  an  even-calibered  stem  is 
selected,  and  the  lower  end  of  the  stem  plugged  with  a 
little  absorbent  cotton,  upon  which  a  layer  three  or  four 
mm.  deep  of  the  filter-material  is  placed.  The  requisite 


64  ANALYTIC   OPERATIONS. 

volume  of  water  is  then  allowed  to  filter  through.  The 
pledget  of  cotton  is  removed,  and  the  filter-material  is 
washed  down  with  filtered  or  distilled  water  into  a  cell 
intended  for  microscopic  examination.  This  cell  is  a  glass 
plate  accurately  ruled,  to  which  is  attached  a  brass  cell  50 
mm.  long  by  10  mm.  wide,  of  depth  sufficient  to  hold 
about  two  c.c.  of  water.  After  the  material  has  been 
allowed  to  distribute  itself  and  settle  in  the  cell,  it  is 
examined  with  a  moderate  power,  and  the  different  organ- 
isms in  a  varying  number  of  the  squares  counted.  Each 
organism  may  be  counted  by  itself,  if  occurring  in  large 
numbers,  the  average  of  a  few  squares  being  sufficient  for 
the  purpose.  Organisms  less  numerously  represented  may 
be  counted  by  averaging  a  larger  number  of  squares. 

Filtering  in  this  manner  cannot  be  relied  upon  in  all 
cases.  Indeed,  in  most  cases  the  unfiltered  water  also 
should  be  examined.  Some  of  the  minute  unicellular 
organisms  pass  readily  through  the  small  extent  of  sand  or 
precipitated  silica,  or  even  through  filter  paper. 

It  is  not  unlikely  that  the  high-speed  centrifugal  appara- 
tus now  used  in  laboratories,  associated  with  the  employ- 
ment of  some  fine  precipitant  will  aid  in  these  investiga- 
tions. (See  Addenda,  p.  136.) 

The  introduction  of  the  ova  of  entozoa  into  the  human 
system  by  means  of  water  is  doubtless  a  very  common 
occurrence,  and  cases  have  been  reported.  One  of  the 
most  striking  of  these  was  the  anemia  occurring  among  the 
workmen  in  the  St.  Gothard  tunnel,  which  was  found  to 
be  due  to  the  ingestion  of  the  ova  of  a  parasitic  animal, 
Anchylostomum  duodenale. 

Culture  Media. — For  bacteriologic  examinations,  cul- 
ture media  prepared  with  gelatin  or  agar-agar,  are  gen- 


SANITARY    EXAMINATIONS.  65 

erally  used.  In  special  cases  potatoes  and  blood-serum  are 
employed.  In  all  cases  solutions  and  vessels  must  be 
thoroughly  sterilized.  This  is  most  easily  accomplished  in 
the  Arnold  steam  sterilizer.  It  consists  of  a  copper  boiler, 
in  the  form  of  an  inverted  funnel,  which  communicates 
with  the  sterilizing  chamber.  A  double  casing  is  so 
arranged  that  the  condensed  steam  falls  into  the  pan  and 
returns  to  the  boiler.  This  pan  should  be  about  half-filled 
with  water  before  starting.  This  apparatus  is  suitable  not 
only  for  all  sterilizations,  but  also  for  preparing  solutions 
and  for  hot  filtrations. 

Meat- extract-peptone-gelatin : — 

Water, 1000  c.c. 

Meat  extract, 5  grams 

Gelatin, 150      " 

Peptone, 10      " 

Glucose, 2      " 

The  materials,  which  should  be  of  good  quality,  are  dis- 
solved by  heat  and  the  solution  rendered  slightly  alkaline 
by  the  addition  of  sodium  carbonate  or  trisodium  phos- 
phate, added  by  small  portions,  stirring  between  each 
addition,  and  testing  the  liquid  by  placing  a  drop  of  it  on 
red  litmus  paper.  When  the  alkaline  reaction  appears,  the 
liquid  is  filtered  through  good  filter  paper,  the  funnel  and 
beaker  being  placed  in  the  sterilizer,  and  a  gentle  steaming 
maintained  in  order  to  keep  the  gelatin  liquid. 

In  place  of  meat  extract,  a  solution  may  be  made  as  fol- 
lows: macerate  500  grams  of  finely  minced  lean  meat  in 
1000  c.c.  of  water,  for  twenty-four  hours,  at  a  temperature 
not  over  45°  F.  Strain  the  liquid,  add  five  grams  of 
common  salt  and  the  peptone,  gelatin  and  glucose,  and 
render  feebly  alkaline,  as  before.  (See  Addenda,  p.  137.) 


66  ANALYTIC   OPERATIONS. 

Agar-agar  Mixture. — When  cultures  are  to  be  conducted 
at  a  temperature  above  68°  F.,  agar-agar  must  be  used  as 
gelatinizing  ingredient.  The  solution  is  prepared  as  given 
above,  except  that  only  15  grams  of  agar-agar  must  be 
used  and  a  much  longer  time  will  be  required  for  its  solu- 
tion. The  operation  can  be  facilitated  by  soaking  the 
agar-agar  for  twelve  hours  in  a  strong  solution  of  common 
salt,  or  by  the  following  treatment,  which  was  first  described 
by  Mace:  — 

Twenty  grams  of  agar-agar,  cut  fine,  are  steeped  for 
twenty-four  hours  in  500  c.c.  of  water,  containing  six  per 
cent,  of  hydrochloric  acid,  with  occasional  stirring.  It  is 
then  well  washed,  and  placed  for  a  similar  period  in  the 
same  amount  of  water,  to  which  six  per  cent,  of  ammonium 
hydroxid  has  been  added.  It  is  again  washed  thoroughly 
and  added  to  1000  c.c.  of  boiling  water.  It  dissolves  at 
once.  The  peptone,  gelatin  and  salt  can  then  be  added, 
the  mixture  rendered  feebly  alkaline  and  filtered  in  the 
sterilizer. 

Agar-agar  Gelatin. — To  secure  the  advantages  of  both 
agar-agar  and  gelatin,  a  solution  may  be  made  by  dissolv- 
ing 50  grams  of  gelatin  and  7.5  grams  of  agar-agar  in  a 
liter  of  water,  adding  the  peptone,  etc.,  in  the  usual  pro- 
portions, rendering  alkaline,  filtering  and  sterilizing.  The 
proportions  of  agar-agar  and  gelatin  must  be  adhered  to 
closely  or  the  gelatinization  may  be  lumpy  and  incomplete. 

Potato  Culture. — Cultivation  on  potatoes  was  once  much 
used  as  a  method  of  distinguishing  certain  microbes. 
Large,  sound  potatoes  should  be  selected,  thoroughly 
washed,  and  cut  into  disks  about  five  cm.  in  diameter  and 
one  cm.  thick.  These  are  placed  in  glass  boxes  (pomade 
boxes)  which  have  lids  with  ground  joint,  and  heated  for 


SANITARY    EXAMINATIONS.  67 

about  one-half  hour  in  the  sterilizer.  Another  method  is 
to  cut  out  cylinders  with  the  aid  of  an  apple-corer,  or 
largest  size  cork-borer,  slice  these  obliquely,  and  place 
them  in  test-tubes,  which  are  then  closed  with  cotton  plugs, 
and  sterilized.  The  latter  method  does  not  give  a  large 
surface,  but  the  growth  of  any  inoculation  may  be  easily 
watched. 

Collection  of  Samples. — Bacteriologic  examinations 
are  of  little  value  unless  promptly  made  on  samples  that 
have  been  collected  with  precautions  against  contamina- 
tion. The  inoculation  of  the  culture-medium  is  best  done  at 
the  source.  If  this  is  not  possible,  glass-stoppered  bottles 
holding  about  200  c.  c.,  which  have  been  thoroughly  steril- 
ized, with  stoppers  in  place,  in  a  hot  air  oven  at  200°  F., 
must  be  used  for  collection.  They  should  be  rinsed  on 
the  outside  with  water,  dipped  below  the  surface,  the 
stopper  withdrawn,  and  again  inserted  when  the  bottle  is 
full.  If  these  are  to  be  transported  any  distance  they 
should  be  packed  in  ice.  For  delivering  the  measured 
volume  of  water,  a  pipette  sterilized  in  the  hot-air  oven 
should  be  used. 

Culture  Manipulations. — For  the  estimation  and 
isolation  of  microbes  in  water,  several  methods  may  be  em- 
ployed, either  the  original  plate-culture  of  Koch,  Es- 
march's  "  roll-culture,"  or  a  modification  that  Dr.  Beam 
and  I  have  used,  which  may  be  designated  "  bottle  cul- 
ture." 

Plate-culture. — Test-tubes  containing  about  10  c.  c.  of 
nutrient  jelly  are  plugged  with  cotton  and  steamed  for 
fifteen  minutes  in  the  sterilizer  on  two  successive  days.  In 
filling  the  tubes,  care  must  be  taken  that  none  of  the  jelly 
touches  the  upper  part,  where  it  can  come  in  contact  with 


68  ANALYTIC   OPERATIONS. 

the  cotton  plug.  After  sterilization,  the  tubes  should  be 
put  aside  for  a  few  days,  to  determine  if  all  spores  are 
destroyed.  If  no  development  of  microbes  takes  place 
in  this  time,  the  jelly  is  ready  for  use.  It  should  be  melted 
at  a  low  temperature  in  a  water-bath,  the  cotton  plug  re- 
moved with  a  twisting  motion  and  a  measured  volume  of 
water  introduced  by  means  of  a  sterilized  pipette.  The 
plug  is  immediately  replaced  and  the  liquids  mixed  by 
shaking,  taking  care  not  to  soil  the  cotton.  The  quantity 
of  water  to  be  added  will  depend  on  the  number  of 
microbes  supposed  to  be  present.  If  the  amount  is  pro- 
bably quite  small,  one  c.  c.  should  be  taken ;  if  it  is 
probable  that  a  large  number  is  present,  one  c.  c.  of  the 
sample  should  be  diluted  to  10  c.  c.  with  sterilized  water, 
and  one  c.  c.  of  this  mixture  used.  In  most  cases  it  will 
be  well  to  make  several  cultures,  using  different  proportions 
of  water.  After  the  jelly  and  water  have  been  mixed  the 
liquid  is  poured  out  on  a  glass  plate  and  allowed  to  set. 
The  principal  difficulty  in  the  method  arises  from  the 
liability  to  contamination  from  the  air  during  this  part  of 
the  process.  The  glass  plates  should,  of  course,  be 
•thoroughly  sterilized.  They  are  usually  set  upon  glass 
benches,  and  placed  in  a  so-called  moist  chamber,  which 
consists  of  two  cylindrical  glass  dishes,  one  fitting  within 
the  other.  The  benches  and  plates  are  placed  in  the  inner 
dish.  To  hasten  the  setting  of  the  jelly,  it  is  necessary 
that  the  plates  should  be  cold,  and  it  will  be  best  to  have 
them  resting  in  a  level  position  on  a  flat  tin  bottle  filled 
with  ice  water,  or,  if  ice  is  not  at  hand,  a  recently  prepared 
mixture  of  one  part  of  ammonium  nitrate  with  two  parts  of 
water.  The  coated  plates  must  be  protected  from  dust 
while  being  cooled,  and  as  soon  as  possible  must  be  trans- 


SANITARY    EXAMINATIONS.  69 

ferred  to  the  moist  chamber,  which,  as  well  as  the  benches, 
should  have  been  previously  thoroughly  washed  with 
recently  boiled  water.  The  bottom  should  be  covered 
with  a  sheet  of  moist  filter-paper.  The  plates  are  kept  in 
the  chamber  for  several  days.  Each  living  microbe  that  is 
capable  of  growing  in  the  medium  will  become  the  center 
of  a  colony  of  its  own  kind,  which  will  soon  become  visible 
to  the  naked  eye.  The  number  of  colonies  may  be 
counted  as  soon  as  they  are  distinct.  When  the  number 
is  very  large,  an  approximate  counting  may  be  made  by 
means  of  a  glass  plate  with  lines  ruled  so  as  to  divide  it 
into  a  considerable  number  of  equal  squares.  This  is 
placed  over  the  culture,  and  the  number  of  colonies  in 
several  of  the  squares  counted,  the  result  averaged  and 
multiplied  by  the  number  of  squares  that  the  entire  culture 
covers. 

Roll  Culture. — Instead  of  pouring  the  jelly  on  a  plate, 
it  may  be  spread  in  a  uniform  layer  on  the  inner  wall  of  the 
test-tube,  taking  care  not  to  allow  it  to  touch  the  cotton. 
The  jelly  may  be  rapidly  hardened  by  rolling  the  tube  in 
contact  with  ice.  The  method  avoids  all  danger  of  con- 
tamination with  dust,  and  is  very  simple  in  manipulation, 
but  is  open  to  the  objection  that  when  bacilli  are  present 
which  liquefy  the  gelatin,  as  will  generally  be  the  case,  the 
fluid  will  run  down  and  inoculate  other  portions  of  the  layer. 
.  Bottle  Culture. — To  avoid  the  disadvantage  of  the  above 
methods,  it  will  be  found  convenient  to  employ  .flat 
rectangular  bottles  of  the  form  known  technically  as  the 
"Blake"  Bottle.  Those  of  8  or  10  ounce  capacity  are 
the  best,  and  it  is  well  to  select  such  as  have  as  uniform  a 
thickness  of  glass  as  possible.  They  should  be  thoroughly 
cleaned  and  sufficient  of  the  jelly  put  in  to  form  a  thin 


70  ANALYTIC    OPERATIONS. 

layer  on  one  of  the  broader  sides  when  the  bottle  is  placed 
horizontally.  The  mouth  is  then  closed  by  a  cotton-plug 
and  the  bottle  sterilized  as  described  in  connection  with 
plate  culture.  To  make  a  culture,  the  jelly  is  melted  at  a 
low  temperature,  the  measured  volume  of  water  added, 
the  cotton  plug  replaced,  and  after  mixing,  the  bottle  is 
placed  in  a  horizontal  position  for  the  usual  time. 

General  Character  of  the  Microbes  in  Natural 
Waters. — The  microorganisms  of  natural  waters  are  prin- 
cipally included  in  the  genera  Bacillus  and  Spirillum, 
especially  the  former.  Micrococci  and  moulds  are  rare, 
and  when  they  appear  on  the  culture-plate,  are  generally 
due  to  contamination  by  dust. 

Microbes  are  distinguished  according  to  the  conditions 
favorable  to  their  growth,  as  follows: — 

Saprophytic.     Growing  on  dead  matter. 

Parasitic.     Growing  only  on  living  matter. 

Aerobic.     Requiring  free  oxygen. 

Anaerobic.     Not  requiring  free  oxygen. 

When  the  organism  possesses  the  power  of  adapting  itself 
to  different  conditions,  the  term  facultative  is  applied ; 
when  it  can  grow  only  under  special  conditions,  the  term 
obligatory  is  applied. 

Microbes  are  also  differentiated  by  the  effect  which  they 
produce  upon  the  culture-medium.  Some  species  rapidly 
or  slowly  liquefy  the  jelly  with  evolution  of  foul  smelling 
gases ;  others — chromogenic  microbes — produce  character- 
istic colors.  Many  do  not  produce  any  positive  modifica- 
tion, and  for  purposes  of  distinction  it  is  usual  to  transfer 
portions  of  the  colonies  to  other  culture-media.  Such 
special  cultures  are  obtained  by  taking  up  a  portion  of 
the  colony  on  the  end  of  a  wire  which  has  been  just 


SANITARY    EXAMINATIONS. 


71 


sterilized  by  heating  to  redness  and  inoculating  the  pre- 
pared medium. 

Cultivation  in  Absence  of  Oxygen. — Several  of  the  most 
frequently  occurring  microbes  are  obligatory  anaerobes, 
and  will  grow,  therefore,  only  in  an  atmosphere  deprived 
of  free  oxygen.  Carbon  dioxid  has  been  found  to  act 
unfavorably  upon  their  development.  The  most  suitable 
atmosphere  is  one  of  pure  hydrogen.  Cultivation  in  such 
an  atmosphere  may  be  secured  by  constructing  the  moist 
chamber  so  as  to  permit  its  being  filled  with  hydrogen  and 
sealed,  or  by  the  use  ofLiborius'  tube,  Fig.  8. 

The  tube  is  charged  with  nutrient  jelly, 
plugged  with  cotton,  sterilized,  inoculated 
with  the  material  to  be  tested,  the  jelly 
maintained  in  a  liquid  condition  by  a  very 
gentle  heat  and  a  current  of  pure  hydrogen 
passed  through  the  side  tube  until  all  air  is 
expelled.  The  test-tube  and  side-tube  are 
then  sealed  quickly  at  the  narrow  portions, 
in  the  blow-pipe  flame,  and  the  jelly  allowed 
to  solidify. 

Staining. — The  differentiation  of  the  various  species  of 
microbes  may  also  be  accomplished  by  staining  with 
various  anilin  colors.  These  methods  are,  however,  more 
generally  applicable  to  pathologic  work,  that  is,  to  the 
staining  of  microbes  in  tissues. 

Indol  Reaction. — Indol,  C8H7N,  more  properly  indin,  is  a 
weak  base,  which  is  a  product  of  the  growth  of  many  species 
of  microbes,  and  the  detection  of  it  may,  therefore,  be  util- 
ized as  a  differentiation  test.  S.  Kitasato  (Zeit.  /.  Hyg. ,  vn, 
518)  gives  the  following  method  for  performing  the  test: — 

Ten  c.  c.  of  an  alkaline-peptone-meat  infusion  (without 


72  ANALYTIC   OPERATIONS. 

gelatin),  which  has  been  previously  inoculated  with  the 
microbes  to  be  tested,  and  kept  for  twenty-four  hours  at 
blood  heat,  are  treated  with  one  c.  c.  of  solution  of  pure 
potassium  nitrite  (0.02  grm.  in  100  c.  c.)  and  then  with 
a  few  drops  of  concentrated  sulphuric  acid.  In  the  pres- 
ence of  indol  a  rose  or  deep-red  color  is  developed.  Spi- 
rillum cholertz  and  Bacillus  coli-communis  give  the  reaction 
strongly ;  S.  Finkleri  feebly ;  the  so-calied  B.  typhosus 
does  not  give  it. 

An  effort  has  been  made  to  distinguish  dangerous  mi- 
crobes by  employing  crucial  conditions  of  cultivation 
which  are  believed  to  eliminate  the  harmless  forms.  One 
of  the  most  complete  methods  is  that  used  in  the  Hygi- 
enic Laboratory  of  the  University  of  Michigan,  under  the 
supervision  of  Dr.  Vaughan  : — 

The  water  is  collected  in  sterilized  bottles,  and  beef-tea 
tubes  are  inoculated  with  it,  from  one  drop  to  one  cubic 
centimeter  being  added  to  each  tube.  The  inoculated 
tubes  are  kept  at  38°  C.  for  twenty-four  hours. 

Many  germs  found  in  drinking-water  will  not  grow  at 
so  high  a  temperature.  It  is  assumed  that  a  germ  which 
will  not  grow  at  the  temperature  of  the  human  body  can- 
not possibly  induce  disease.  Of  the  germs  which  do  grow 
at  38°,  or  higher,  some  are  toxicogenic  to  animals,  while 
others  are  not.  Whether  the  germs  in  a  given  sample 
are  toxicogenic  or  not,  is  determined  by  injecting  the  pre- 
pared cultures  subcutaneously  or  intra-abdominally  in  rats, 
guinea-pigs,  rabbits,  or  mice. 

Waters  not  containing  toxicogenic  germs  growing  at 
38°  or  higher  are  reported  as  safe. 

Waters  containing  toxicogenic  germs  growing  at  38°  C. 
are  condemned.  In  testing  virulence,  a  germ  is  not 


SANITARY    EXAMINATIONS.  73 

pronounced  toxicogenic  unless  it  be  found  growing  and 
multiplying  in  the  animal  inoculated  with  it. 

The  Franklands  ("Microorganisms  in  Water"),  after 
reviewing  at  length  the  various  methods  that  have  been 
suggested  for  differentiating  the  typhoid-bacillus,  show 
that  most  of  them  are  quite  insufficient.  A  routine  treat- 
ment is,  however,  suggested  as  follows:  — 

The  water  is  freed  from  the  ordinary  water-bacteria 
by  preliminary  culture  in  Parietti's  solution.  This  is  a 
phenol-broth  prepared  by  mixing  10  c.  c.  of  neutral 
bouillon  with  0.25  c.  c.  of  the  following  solution  : — 

Phenol, 5  grams. 

Hydrochloric  acid 4       " 

Water,       loo       " 

This  solution  is  sterilized  by  heating  it  for  twenty-four 
hours  at  37°  C.  The  tubes  are  then  inoculated  with  from 
one  to  ten  drops  of  the  water-sample,  which  must  be 
thoroughly  mixed  with  the  broth,  and  again  kept  in  the 
sterilizer  for  not  less  than  forty-eight  hours.  If  any  of 
the  tubes  appear  turbid  after  the  treatment,  they  should  be 
submitted  to  plate-cultivation,  and  any  colonies  which 
resemble  those  produced  by  the  typhoid-bacillus  should  be 
further  studied  by  inoculation  into  gelatine  tubes  to  observe 
the  gas -producing  test,  into  milk  to  note  if  coagulation 
occurs,  and  by  cultivation  in  broth  to  determine  if  indol- 
reaction  will  be  obtained. 

Hazen  and  White  ("  Manual  of  Bacteriology,"  Stern- 
berg,  p.  354)  cultivate  the  water  in  agar-agar  tubes  at 
40°  C.  for  several  days,  which  prevents  the  growth  of 
many  of  the  common  water-microbes. 

Vaughan  ("Proceedings  American  Association  of  Phy- 
sicians, 1892")  investigated  the  application  of  these  prin- 


74  ANALYTIC   OPERATIONS. 

ciples  to  the  isolation  of  a  specific  bacillus,  but  did  not 
obtain  satisfactory  results. 

From  the  Franklands'  work  I  take  the  description  of 
methods  used  for  detection  of  the  Spirillum  cholera  in  water. 
According  to  Koch,  100  c.  c.  of  water  is  mixed  with  one 
per  cent,  each  of  peptone  and  common  salt  and  the  mix- 
ture kept  at  37°  C.  At  intervals  of  ten,  fifteen,  and  twenty 
hours  plate-cultivations  are  made  of  portions  of  the  sample. 
Any  colonies  which  appear  on  the  plates  should  be  re- 
inoculated  into  fresh  culture-media  and  be  tested  after  a 
time  for  indol. 

Schottelius  recommends  the  following :  The  water  is 
mixed  with  twice  its  volume  of  alkaline  sterile  bouillon, 
and  kept  at  a  temperature  of  30-40°  C.  for  twelve  hours. 
An  extensive  multiplication  of  the  spirillum  occurs  on  the 
surface  of  the  liquid,  and  the  examination  of  the  pellicle 
will  show  many  of  them. 

Klein  {Br.  Med.  Jour.,  Oct.  14,  1894)  has  pointed  out 
that  in  most  of  the  methods  for  isolating  pathogenic 
microbes,  the  volume  of  water  used  is  too  small.  He 
suggests  the  employment  of  at  least  1000  c.  c.  Obviously 
this  volume  will  give  a  better  sampling  than  the  few  drops 
or  i  c.  c.  generally -used. 


TECHNIC  EXAMINATIONS. 

GENERAL  QUANTITATIVE  ANALYSIS. 

Silica,  Iron,  Aluminum,   Manganese,  Calcium, 

and  Magnesium. — One  liter  of  the  water  acidified  with 

hydrochloric  acid  is  evaporated  to  complete  dryness,  best 

in  a  platinum  dish,  the  residue  treated  with  hydrochloric 


TECHNIC   EXAMINATIONS.  75 

acid  and  water,  and  the  separated  silica  filtered,  washed, 
dried,  ignited  in  a  platinum  crucible,  and  weighed. 

To  the  filtrate,  previously  boiled  with  a  few  drops  of 
strong  nitric  acid,  slight  excess  of  ammonium  hydroxid  is 
added,  the  liquid  boiled  several  minutes,  the  precipitate 
collected,  washed  thoroughly  with  boiling  water,  dried, 
ignited,  and  weighed.  It  consists  of  J?e2Os  and  Al^O3.  It 
also  contains  all  the  phosphates  and  some  manganese  if 
much  is  present  in  the  water.  In  such  cases  the  precipitate 
before  drying  is  re-dissolved  in  hydrochloric  acid  and 
neutralized  with  a  dilute  solution  of  ammonium  carbonate 
until  the  water  almost  becomes  turbid.  It  is  then  boiled 
and  the  precipitate,  now  free  from  manganese,  washed, 
dried,  ignited,  and  weighed.  The  iron  may  be  determined 
by  dissolving  the  precipitate  in  strong  hydrochloric  acid 
and  employing  the  colorimetric  method  described  on  page 

38- 

If  no  manganese  or  only  traces  are  present,  the  filtrate 
from  the  iron  is  mixed  with  sufficient  ammonium  chlorid 
to  prevent  the  precipitation  of  the  magnesium,  ammonium 
hydroxid,  and  then  ammonium  oxalate  added  in  quantity 
sufficient  to  precipitate  the  calcium  and  to  convert  all  the 
magnesium  into  oxalate,  and  thus  hold  it  in  solution.  The 
precipitate  contains  all  the  calcium  and  some  of  the  mag- 
nesium. If  the  magnesium  is  present  only  in  relatively 
smallquantity  the  amount  carried  down  may  be  disregarded; 
otherwise  a  second  precipitation  should  be  made  as  follows  : 
The  solution  is  allowed  to  stand  until  the  precipitate  has 
subsided  ;  this  will  require  some  hours.  The  supernatant 
liquid  is  poured  off  through  a  filter,  the  precipitate  washed 
by  decantation,  then  dissolved  in  hydrochloric  acid,  water 
added,  then  ammonium  hydroxid  and  a  small  quantity 


76  ANALYTIC   OPERATIONS. 

of  ammonium  oxalate.  After  the  calcium  oxalate  has 
thoroughly  subsided  it  is  filtered  off,  washed,  and  dried.  If 
quite  small  in  amount  it  is  placed  with  the  filter  in  a  weighed 
platinum  crucible,  ignited  over  the  Bunsen  burner  for  a 
short  time,  and  then  over  the  blast  lamp  for  from  five  to 
fifteen  minutes.  The  calcium  is  thus  obtained  in  the  form 
of  oxid,  which  is  allowed  to  cool  in  the  desiccator  and 
weighed.  The  weight  thus  obtained  multiplied  by  0.714 
gives  the  weight  of  calcium.  When  the  amount  of  precipi- 
tate is  large,  it  is  better  to  remove  it  from  the  filter,  and 
heat  it  just  short  of  redness  until  it  assumes  a  grayish  tint. 
It  then  consists  of  calcium  carbonate.  To  this  is  added 
the  ash  of  the  filter.  The  weight  of  the  calcium  carbonate 
multiplied  by  0.4  gives  the  weight  of  calcium. 

The  filtrates  are  mixed,  slightly  acidified  with  hydro- 
chloric acid,  concentrated  and  cooled,  ammonium  hydroxid 
and  sodium  phosphate  added  in  excess,  stirred  briskly 
and  allowed  to  stand  in  the  cold  for  about  twelve  hours. 
The  precipitated  ammonium  magnesium  phosphate  is 
brought  upon  a  filter,  that  adhering  to  the  sides  of  the  ves- 
sel being  dislodged  by  rubbing  with  a  glass  rod  tipped  with 
a  piece  of  clean  rubber  tubing.  It  is  washed  with  a  solu- 
tion made  by  mixing  one  part  of  the  ammonium  hydroxid 
of  0.96  sp.  gr.  with  three  parts  of  water.  The  precipitate 
is  dried,  transferred  to  a  platinum  crucible,  the  filter  ashed 
separately  and  added  to  it,  and  the  whole  heated  at  first 
gently  and  then  to  intense  redness  for  several  minutes. 
After  cooling,  it  is  weighed.  It  consists  of  magnesium 
pyrophosphate ;  the  weight  multiplied  by  0.218  gives  the 
weight  of  magnesium. 

Manganese,  if  present  in  appreciable  quantity,  is  sepa- 
rated before  the  precipitation  of  the  calcium,  as  follows  : 


TECHNIC    EXAMINATIONS.  77 

The  filtrate  from  the  iron  precipitate  is  slightly  acidulated 
with  hydrochloric  acid,  concentrated,  and  the  manganese 
precipitated  as  sulphid  by  colorless  or  slightly  yellow  solu- 
tion of  ammonium  sulphid.  The  flask,  which  ^should  be 
nearly  full,  is  stoppered,  allowed  to  rest  in  a  moderately 
warm  place  until  the  precipitate  has  thoroughly  settled, 
filtered,  washed  with  dilute  ammonium  sulphid  water  and 
purified  by  dissolving  in  a  small  quantity  of  hydrochloric 
acid  and  reprecipitating  with  ammonium  sulphid.  It  is 
filtered  off,  washed  as  before,  dried,  placed  in  a  weighed 
porcelain  crucible,  covered  with  a  little  sulphur  and  ignited 
in  a  current  of  hydrogen  introduced  into  the  crucible  by  a 
tube  passing  through  a  hole,  in  the  cover.  The  pure  man- 
ganese sulphid  thus  obtained  is  allowed  to  cool  and 
weighed.  The  weight  multiplied  by  .632  gives  man- 
ganese. 

Sulphates. — 500  c.  c.  of  the  clear  water  are  slightly 
acidulated  with  hydrochloric  acid,  heated  to  boiling,  and 
barium  chlorid  solution  added  in  moderate  success.  The 
precipitate  is  allowed  to  subside  completely,  collected  upon 
a  filter,  washed  thoroughly,  dried  and  incinerated.  It  is 
BaSO4;  the  weight  multiplied  by  0.412  gives  SO4.  If  the 
proportion  of  SO4  is  very  low,  it  will  be  advisable  to  con- 
centrate the  water  to  one-fifth  or  one-tenth  its  bulk  before 
precipitating. 

Control.  Potassium,  Sodium,  and  Lithium. — 
From  250  to  1000  c.  c.  of  the  water,  according  to  the 
amount  of  solid  matters  present,  are  evaporated  to  dryness 
in  a  platinum  dish,  and  the  residue  treated  with  a  small 
amount  of  water  and  sufficient  dilute  sulphuric  acid  to 
decompose  the  salts  present.  The  dish  should  then  be 
covered  and  placed  upon  the  water-bath  for  five  or  ten 


78  ANALYTIC   OPERATIONS. 

minutes,  after  which  any  liquid  spurted  on  the  cover  is 
washed  into  the  dish,  the  whole  evaporated  to  dryness 
and  heated  to  redness.  A  few  drops  of  ammonium 
carbonate  solution  should  then  be  mixed  with  the  resi- 
due, and  the  ignition  repeated  to  insure  the  removal  of 
the  last  portions  of  free  acid.  In  the  majority  of  cases 
the  only  basic  elements  present  in  considerable  quantity 
are  calcium,  magnesium,  and  sodium.  The  sodium  may  be 
determined  indirectly,  therefore,  by  calculating  from  the 
amount  of  Ca  and  Mg  found,  the  calcium  and  magne- 
sium sulphate  in  the  residue,  and  subtracting  this  sum, 
together  with  the  silica,  from  the  total  residue. 

For  the  determination  of  potassium  and  sodium  in  ordin- 
ary well  and  river  waters,  not  less  than  two  liters  should  be 
employed.  When  lithium  is  to  be  determined,  it  is  gener- 
ally necessary  to  use  much  more.  In  any  case,  as  the  alkalies 
are  to  be  weighed  as  chlorids,  it  is  advisable,  if  notable 
amounts  of  sulphates  are  present,  to  precipitate  them  by 
addition  of  barium  chlorid. 

The  water  is  evaporated  to  about  200  c.  c.,  a  slight 
excess  of  calcium  hydroxid  added  to  the  hot  liquid — gen- 
erally 3  c.  c.  of  thin  milk  of  lime  will  be  sufficient — and  the 
heat  continued  for  several  minutes.  It  is  then  washed  into 
a  250  c.  c.  flask,  disregarding  the  insoluble  portion  ad- 
hering to  the  dish,  which,  however,  should  be  thoroughly 
washed,  and  the  washings  added  to  the  flask.  After  cool- 
ing, the  flask  is  filled  up  to  the  mark  with  distilled  water, 
thoroughly  mixed,  the  precipitate  allowed  to  settle,  and 
the  liquid  filtered  through  a  dry  filter.  200  c.  c.  of  the 
filtrate  are  measured  into  another  250  c.  c.  flask, 
ammonium  carbonate  and  ammonium  oxalate  added, 
filled  with  water  up  to  the  mark,  mixed,  allowed  to  settle, 


TECHNIC    EXAMINATIONS.  79 

filtered  through  a  dry  filter,  200  c.  c.  of  the  filtrate 
measured  off  and  evaporated  to  thorough  dryness  in  a 
platinum  crucible,  heating  very  cautiously  at  the  last  stages 
to  avoid  loss  by  spurting.  The  low-temperature  burner  is 
suited  for  this  purpose.  The  crucible  is  now  covered  and 
cautiously  heated  to  dull  redness,  cooled  and  weighed. 
The  residue  contains  the  potassium,  lithium  and  sodium 
as  chlorids.  It  contains,  sometimes,  also,  traces  of  mag- 
nesium, which  may  be  removed  by  treating  again  with 
lime  and  ammonium  carbonate  and  oxalate.  It  is  fre- 
quently of  advantage,  in  evaporating  these  saline  solutions, 
to  add,  when  the  solution  becomes  concentrated,  several 
c.  c.  of  strong  hydrochloric  acid.  This  precipitates  the 
greater  portion  of  the  salts  in  a  finely  granular  condition, 
and  renders  loss  by  spurting  less  liable  to  occur. 

If  potassium  and  sodium  chlorids  only  are  present,  the 
residue  is  dissolved  in  a  small  quantity  of  water,  an 
excess  of  a  concentrated  neutral  solution  of  platinum 
chlorid  added,  evaporated  to  small  bulk  at  a  low  heat 
on  the  water  bath,  some  80  per  cent,  alcohol  added, 
allowed  to  stand,  the  clear  liquid  decanted  off  on  a 
small  filter  and  the  residue  washed  in  this  way  several 
times  by  fresh  small  portions  of  80  per  cent,  alcohol.  The 
precipitate  is  then  washed  on  to  the  filter  with  alcohol, 
washed  again  with  80  per  cent,  alcohol,  thoroughly  dried 
and  transferred  as  far  as  possible  to  a  watch  glass.  The 
small  portion  on  the  filter  is  dissolved  off  and  the  solution 
placed  in  a  weighed  platinum  dish  and  evaporated  to  dry- 
ness.  The  main  portion  on  the  watch  glass  is  then  added, 
and  the  whole  dried  to  a  constant  weight  at  about  260°  F. , 
cooled  and  weighed.  The  weight  thus  found  multiplied 
by  .30  gives  the  weight  of  potassium  chlorid.  This  sub- 


80  ANALYTIC    OPERATIONS. 

tracted  from  the  combined  weight  of  the  chlorids  gives 
the  weight  of  sodium  chlorid. 

Lithium,  if  present,  is  best  separated  before  the  treatment 
with  platinum  chlorid.  The  following  method,  devised 
by  Gooch,  gives  good  results:  To  the  concentrated  solu- 
tion of  the  weighed  chlorids,  amyl  alcohol  is  added  and 
heat  applied,  gently  at  first,  to  avoid  bumping,  until  the 
water  disappears  from  the  solution  and  the  point  of  ebulli- 
tion becomes  constant  at  a  temperature  which  is  approxi- 
mately that  at  which  the  alcohol  boils  (270°  F.),  the 
potassium  and  sodium  chlorids  are  deposited  and  the 
lithium  chlorid  is  dehydratejd  and  taken  into  solution. 
The  liquid  is  then  cooled  and  a  drop  or  two  of  strong 
hydrochloric  acid  added  to  reconvert  traces  of  lithium  hy- 
droxid  in  the  deposit,  and  the  boiling  continued  until  the 
alcohol  is  again  free  from  water.  If  the  amount  of  lithium 
chlorid  be  small,  it  will  be  found  in  the  solution  and  the 
potassium  chlorid  and  sodium  chlorid  in  the  residue, 
excepting  traces  which  can  be  allowed  for.  If  the  lithium 
chlorid  exceed  ten  or  twenty  milligrams  the  liquid  may  be 
decanted,  the  residue  washed  with  amyl  alcohol,  dissolved 
in  a  few  drops  of  water  and  treated  as  before.  For  wash- 
ing, amyl  alcohol,  previously  dehydrated  by  boiling,  is  to 
be  used  and  the  filtrates  are  to  be  measured  apart'  from  the 
washings.  In  filtering,  the  Gooch  filter  with  asbestos  felt 
may  be  used  with  advantage,  applying  gentle  pressure  by 
the  aid  of  the  filter  pump.  The  crucible  and  residue  are 
ready  for  weighing  after  gentle  heating  over  the  low-tem- 
perature burner.  The  weight  of  the  insoluble  chlorids  is 
to  be  corrected  by  adding  .00041  for  every  ice.  c.  of  amyl 
alcohol  in  the  filtrate,  exclusive  of  the  washings,  if  only 
sodium  chlorid  be  present ;  .00051  for  every  10  c.  c.  if 


TECHNIC   EXAMINATIONS.  8  I 

only  potassium   chlorid,  and  .00092    in   the  presence  of 
both  these  chlorids. 

The  filtrate  and  washings  are  evaporated  to  dryness  in  a 
platinum  crucible  heated  with  sulphuric  acid,  the  excess 
driven  off,  and  the  residue  ignited  to  fusion,  cooled  and 
weighed.  From  the  weight  is  to  be  subtracted,  for  each 
10  c.  c.  of  filtrate,  .0005,  .00059,  or  .00109,  according  as 
only  sodium  chlorid,  potassium  chlorid,  or  both  were 
present  in  the  original  mixture. 

Hydrogen  Sulphid. — The  following  method  is  taken 
from  Button's  "Volumetric  Analysis:" — 
Reagents  Required:  — 

Centinormal  Iodin. — Dry,  commercial  iodin  is  inti- 
mately mixed  with  one- fourth  its  weight  of  pure  potassium 
iodid  and  gently  heated  between  two  clock-glasses  by 
resting  the  lower  on  a  hot  plate.  The  iodin  sublimes  in  a 
perfectly  pure  condition.  It  is  allowed  to  cool  under  the 
desiccator,  1.265  grams  weighed  out,  together  with  1.8 
grams  of  pure  potassium  iodid,  dissolved  in  about  50  c.  c. 
of  water  and  the  solution  made  up  exactly  to  a  liter.  The 
liquid  must  not  be  heated,  and  care  should  be  taken  that 
no  iodin  vapor  is  lost.  One  c.  c.  is  equivalent  to  .00017 
H2S.  The  solution  is  best  prepared  in  stoppered  bottles, 
which  should  be  completely  filled  and  kept  in  the  dark. 
It  will  not  even  then  keep  very  long,  and  should  be  stand- 
ardized by  titration  with  a  weighed  amount  of  pure  so- 
dium thiosulphate,  which  should  be  powdered  previous  to 
weighing,  and  pressed  between  filter  paper  to  absorb  any 
moisture.  50  c.  c.  of  the  iodin  solution,  when  of  full 
strength,  will  require  0.124  gram  °f  sodium  thiosulphate. 

Starch  Indicator. — See  page  48. 

F 


82  ANALYTIC   OPERATIONS. 

Analytic  Process  :— 

Ten  c.  c.,  or  any  other  necessary  volume  of  the  iodin 
solution,  is  measured  into  a  500  c.  c.  flask,  and  the  water 
to  be  examined  added  until  the  color  disappears.  Five 
c.  c.  of  starch  liquor  are  then  added  and  the  iodin  solution 
run  in  until  the  blue  copper  appears ;  the  flask  is  then  filled 
to  the  mark  with  distilled  water.  The  respective  volumes 
of  iodin  and  starch  solution,  together  with  the  added 
water,  deducted  from  the  500  c.  c.  will  show  the  volume 
of  water  actually  titrated  by  iodin.  A  correction  should 
be  made  as  follows  for  the  excess  of  iodin  required  to  pro- 
duce the  blue  color  :  Five  c.  c.  starch  solution  are  made 
up  with  distilled  water  to  500  c.  c.,  iodin  run  in  until  the 
color  matches  that  in  the  test,  and  the  volume  of  iodin 
solution  so  used  subtracted  from  the  figure  obtained  in  the 
first  titration. 

Hardness.  CO3  in  Normal  Carbonates. — Waters 
containing  considerable  quantities  of  calcium  and  magne- 
sium are  said  to  be  hard.  Since  the  solution  of  calcium 
and  magnesium  carbonate  in  water  depends  partly  upon 
the  presence  of  carbon  dioxid,  boiling  precipitates  the 
greater  portion  of  the  carbonates,  the  result  being  to  di- 
minish the  hardness,  /.  <?.,  to  soften  the  water.  Magne- 
sium and  calcium  sulphates  and  chlorids  are  not  precipi- 
tated in  this  way.  Hardness,  therefore,  is  divided  into 
two  classes,  temporary  and  permanent,  the  former  being 
that  which  may  be  removed  by  boiling.  The  process  here 
described  is  due  to  Hehner. 
Reagents  Required ; — 

Standard  Sodium  Carbonate. — 1.06  grams  of  recently 
ignited  pure  sodium  carbonate  are  dissolved  in  water  and 


TECHNIC    EXAMINATIONS.  83 

the  solution  diluted  to  1000  c.  c.     One  c.  c.  =  .00106  gram 
Na2CO3,  equivalent  to  .001  gram  CaCO3. 

Standard  Sulphuric  Acid. — One  c.  c.  of  pure  concen- 
trated sulphuric  acid  is  added  to  about  1000  c.  c.  of  water. 
50  c.  c.  of  the  standard  sodium  carbonate  are  placed  in  a 
porcelain  dish,  heated  to  boiling,  a  few  drops  of  a  solution 
of  phenacetolin  or  lacmoid  added,  and  the  sulphuric  acid 
cautiously  run  in  from  a  burette  until  the  proper  change  of 
color  occurs.  From  the  figure  thus  obtained,  the  extent 
to  which  the  acid  should  be  diluted  in  order  to  make  one 
c.  c.  of  the  sodium  carbonate  equivalent  to  one  c.  c.  of 
the  acid  may  be  calculated.  The  proper  amount  of  water 
is  then  added  and  the  solution  verified  by  again  titrating. 
Analytic  Process  : — 

Temporary  Hardness. — 100  c.  c.  to  250  c.  c.  of  the  water 
tinted  with  the  indicator  are  heated  to  boiling,  and  the 
sulphuric  acid  cautiously  run  in  until  the  color  change 
occurs.  Each  c.  c.  required  will  represent  one  part  of  cal- 
cium carbonate  or  its  equivalent  per  100,000  parts  of  the 
water. 

Permanent  Hardness. — To  100  c.  c.  of  the  water  is 
added  an  amount  of  the  sodium  carbonate  solution  more 
than  sufficient  to  decompose  the  calcium  and  magnesium 
sulphates,  chlorids  and  nitrates  present ;  usually  a  bulk 
equal  to  the  water  taken  will  be  more  than  sufficient.  The 
mixture  is  evaporated  to  dryness  in  a  nickel  or  platinum 
dish,  and  the  residue  extracted  with  distilled  water.  The 
solution  is  filtered  through  a  very  small  filter,  and  the  filtrate 
and  washings  titrated  hot  with  sulphuric  acid  as  above ;  or 
25  c.  c.  of  distilled  water  may  be  poured  on  the  residue, 
and  the  solution  obtained  filtered  through  a  dry  filter,  the 
filtrate  measured  and  titrated.  The  difference  between 


84  ANALYTIC   OPERATIONS. 

the  number  of  c.  c.  of  sodium  carbonate  used  and  the  acid 
required  for  the  residue  will  give  the  permanent  hardness. 

If  the  water  contains  sodium  or  potassium  carbonate 
there  will  be  no  permanent  hardness,  and  there  will  be 
more  acid  required  for  the  filtrate  than  the  equivalent  of 
the  sodium  carbonate  added.  From  this  excess  the 
quantity  of  sodium  carbonate  in  the  water  may  be  deter- 
mined. 

Since  any  alkali-carbonate  in  the  water  would  be  erro- 
neously calculated  as  temporary  hardness  by  the  direct 
titration,  the  equivalent,  in  terms  of  calcium  carbonate,  of 
the  alkali  carbonate  present  should  be  deducted  from  the 
figure  given  by  the  titration  in  order  to  get  the  true  tem- 
porary hardness. 

The  total  CO3  in  normal  carbonates  is  given'  by  the 
direct  titration  of  the  water  with  dilute  sulphuric  acid. 
One  c.  c.  of  the  acid  is  equivalent  to  .0006  gram  of  CO3. 

Free  Carbonic  Acid. — The  following  process,  due  to 
Pettenkofer,  is  taken  from  Sutton's  "  Volumetric  Analy- 
sis:"— 

A  stoppered  bottle  of  known  capacity,  about  150  c.  c., 
is  filled  at  the  source  by  submergence,  or,  if  taken  from  a 
faucet,  by  allowing  the  stream  to  run  in  with  full  force  for 
some  minutes,  the  nozzle  being  inserted  into  the  neck  of 
the  bottle.  50  c.  c.  of  the  water  are  then  quickly  removed 
by  a  .pipette,  and  the  following  solutions  immediately 
added :  Three  c.  c.  of  a  saturated  solution  of  calcium 
chlorid  and  two  c.  c.  of  a  saturated  solution  of  ammonium 
chlorid  ;  45  c.  c.  of  clear  calcium  hydroxid  solution  of 
known  strength  are  added,  the  flask  well  corked,  the  liquids 
mixed,  and  set  aside  for  at  least  twelve  hours,  to  allow  the 
calcium  carbonate  formed  to  settle  and  become  crystalline 


TECHNIC   EXAMINATIONS.  85 

and  insoluble.  An  aliquot  part  (50  to  100  c.  c.)  of  the 
clear  liquid  is  then  drawn  off  and  titrated  with  decinormal 
acid,  using  phenacetolin  or  lacmoid  as  indicator,  and  from 
the  amount  required  the  entire  proportion  of  calcium  hy- 
droxid  unacted  upon  can  be  determined.  This  being 
deducted  from  the  amount  originally  added,  and  the 
remainder  multiplied  by  .0022,  will  give  the  weight  of 
carbonic  acid  in  the  water  in  excess  of  that  existing  as 
normal  carbonates. 

Boric  Acid. — Detection. — Add  to  one  liter  of  the 
water  sufficient  sodium  carbonate  to  render  it  distinctly 
alkaline.  Evaporate  to  dryness,  acidify  with  hydrochloric 
acid,  moisten  a  slip  of  turmeric  paper  with  the  liquid,  and 
dry  it  at  a  moderate  heat.  In  the  presence  of  boric  acid 
the  paper  will  assume  a  distinct  brown-red  tint. 

Quantitive  determinations  of  boric  acid  are  rarely  re- 
quired. It  exists  in  many  of  the  geyser-waters  of  Yellow- 
stone National  Park,  and  doubtless  in  similar  waters  in 
other  parts  of  the  world.  A  careful  investigation  into  the 
methods  of  quantitive  determination  was  published  by 
Hehner  {The  Analyst,  August,  1891)  and  a  modification  of 
Gooch's  method  is  described  by  Moissan  {Jour.  Soc. 
Chem.  Ind.,  April  i,  1895). 

SPECTROSCOPIC  EXAMINATION. 

For  the  ordinary  spectroscopic  examination  of  a  water 
a  simple  apparatus  will  suffice.  The  arrangement  'figured 
in  the  cut  (Fig.  9)  is  a  small  direct- vision  spectroscope, 
held  in  a  universal  stand,  with  an  adjustable  burner  as  the 
source  of  heat.  The  entire  apparatus  does  not  cost  over 
$15, oo,  and  will  be  found  convenient  and  efficient. 

For  the  examination,  a  liter  or  more  should  be  evapo- 


86  ANALYTIC   OPERATIONS. 

rated  nearly  to  dryness,  a  little  hydrochloric  acid  being 
added  near  the  end  of  the 
process,  the  residue  placed 
in  a  narrow  strip  of  plati- 
num foil  having  the  sides 
bent  so  as  to  retain  the 
liquid,  and  heated  in  the 
flame.  While  this  method 
will  be  sufficient  in  many 
cases,  a  far  better  plan  is 
to  separate  the  substance 
sought  for  in  a  state  of  ap- 
proximate purity  and  then 
examine  with  the  spectro- 
scope. Very  small  traces 
of  lithium,  for  instance, 
may  be  detected  as  follows: 
To  about  a  liter  of  the 
water  sufficient  sodium 
carbonate  is  added  to  pre- 
cipitate all  the  calcium  and 
magnesium,  and  the  liquid 
boiled  down  to  about  one- 
tenth  its  bulk ;  it  is  then  filtered,  the  filtrate  rendered 
slightly  acid  with  hydrochloric  acid  and  evaporated  to  dry- 
ness.  The  residue  is  boiled  with  a  little  alcohol,  which 
will  dissolve  out  the  lithium  chlorid.  The  alcoholic 
solution  is  evaporated  to  dryness,  the  residue  taken  up 
with  a  little  water  and  tested  in  the  flame. 

In  order  to  identify  with  certainty  any  line  which  may 
be  obtained,  it  is  only  necessary  to  hold  in  the  flame  at 
the  same  time  a  wire  which  has  been  dipped  in  a  solution 


TECHNIC   EXAMINATIONS.  87 

of  the  substance  supposed  to  be  present,  and  to  note 
whether  the  lines  produced  by  it  and  the  material  under 
examination  are  identical. 

SPECIFIC  GRAVITY. 

In  the  great  majority  of  cases  the  determination  of 
specific  gravity  is  not  essential.  Ordinary  river,  spring  and 
well  waters  contain  such  small  proportions  of  solid  matter 
that  it  is  usually  the  practice  to  take  a  measured  volume 
and  to  assume  its  weight  to  be  that  of  an  equal  bulk  of 
pure  water.  If  the  proportion  of  solids  be  high,  a  deter- 
mination of  the  specific  gravity  may  be  desirable.  For 
this  purpose  the  specific  gravity  bottle  may  be  used.  This 
consists  merely  of  a  small  flask  provided  with  a  finely  per- 
forated glass  stopper.  The  bottle  is  weighed  first  alone, 
then  filled  with  distilled  water  at  60°  F.,  and  finally  with 
the  water  under  examination  at  the  same  temperature.  In 
filling  the  bottle,  the  liquid  is  first  brought  to  the  proper 
temperature,  the  bottle  completely  filled,  the  stopper  in- 
serted, and  the  excess  of  water  forced  out  through  the 
perforation  and  around  the  sides  of  the  stopper,  carefully 
removed  by  bibulous  paper.  The  weight  of  the  water 
examined  divided  by  the  weight  of  the  equal  bulk  of  dis- 
tilled water  at  the  same  temperature  gives  the  specific 
gravity. 

Another  method,  and  one  which  gives  very  satisfactory 
results,  is  by  the  use  of  a  plummet.  This  may  conveniently 
consist  of  a  piece  of  a  thick  glass  rod  of  about  10  c.  c.  in 
bulk,  or  of  a  test-tube  weighted  with  mercury  and  the  open 
end  sealed  in  the  flame.  The  plummet  is  suspended  to  the 
hook  of  the  balance  by  means  of  a  fine  platinum  wire  and 
its  weight  ascertained.  It  is  then  immersed  in  distilled 


88  ANALYTIC   OPERATIONS. 

water  at  60°  F.,  and  the  loss  in  weight  noted.  The  figure 
so  obtained  is  the  weight  of  a  bulk  of  water  equal  to  that 
of  the  plummet.  This  having  been  determined,  the  specific 
gravity  of  any  water  may  be  found  by  immersing  in  it  the 
plummet  and  noting  the  loss  in  weight.  This,  divided  by 
the  loss  suffered  in  pure  water,  gives  the  specific  gravity. 


INTERPRETATION   OF   RESULTS. 

STATEMENT  OF  ANALYSIS. 

The  composition  of  water  is  generally  expressed  in  terms 
of  a  unit  of  weight  in  a  definite  volume  of  liquid,  but  much 
difference  exists  as  to  the  standard  used.  The  decimal 
system  is  very  largely  employed,  the  proportions  being 
expressed  in  milligrams  per  liter,  nominally  parts  per  mil- 
lion ;  or  in  centigrams  .per  liter,  nominally  parts  per  hun- 
dred thousand.  Not  infrequently  the  figures  are  given  in 
grains  per  imperial  gallon  of  70,000  grains,  or  the  U.  S. 
gallon  of  58,328  grains.  Much  more  rarely  grains  per 
quart,  parts  per  thousand,  per  cent.,  or  other  inconvenient 
ratios  are  employed.  In  this  work  the  composition  is 
always  expressed  in  milligrams  per  liter.  This  ratio  is 
practically  equivalent  to  parts  per  million,  except  in  case 
of  water  very  rich  in  solids,  a  liter  of  which  weighs  nota- 
bly more  than  one  million  milligrams.  Factors  for  con- 
verting the  different  ratios  are  given  at  the  end  of  the 
book. 

From  the  analysis  of  a  water  it  is  rarely  possible  to  ascer- 
tain the  exact  arrangement  of  the  elements  determined,  but 
it  is  the  custom  to  assume  arrangements  based  upon  the 
rule  of  associating  in  combination  elements  having  the 
highest  affinities,  modifying  this  system  by  any  inferences 
derived  from  the  character  or  reactions  of  the  water  itself. 
It  has  been  demonstrated  that,  even  in  the  case  of  mixtures 
89 


90  INTERPRETATION   OF   RESULTS. 

of  salts  producing  no  insoluble  substances,  partial  inter- 
change of  the  basylous  and  acidulous  radicles  takes  place. 
In  a  solution  of  sodium  chlorid  and  potassium  sulphate 
sodium  sulphate  and  potassium  chlorid  will  be  found,  as 
well  as  the  original  salts.  When  the  conditions  are  ren- 
dered more  complex  by  the  addition  of  other  substances, 
it  is  obviously  impossible  to  determine  the  exact  arrange- 
ment. In  view  of  these  facts,  it  is  preferable  to  express 
the  composition  of  a  water  by  the  proportion  of  each  ele- 
ment or  radicle  present.  In  this  way  a  water  containing 
KjSOo  will  be  expressed  in  terms  of  K  and  SO4,  respec- 
tively. In  the  case  of  bodies  like  CO2  and  SiO2,  which  may 
possibly  exist  free  in  the  water,  their  proportion  is  expressed 
as  such.  It  frequently  occurs  that  the  characteristics  of 
some  of  the  compounds  in  a  water  are  sufficiently  marked 
to  indicate  their  presence,  and  there  can  be  no  objection 
to  suggesting,  in  connection  with  the  analytic  statement, 
the  inferences  which  may  thus  be  drawn. 

The  organic  matters,  or  derived  products,  are  best 
stated  in  terms  of  the  nitrogen  which  they  contain,  thus 
permitting  a  comparison  of  the  different  stages  of  decom- 
position. It  is  inadvisable  to  represent  the  amount  of 
unchanged  organic  matter  in  terms  of  oxalic  acid,  as  has 
been  suggested,  or  to  express  the  nitrogen  in  terms  of  albu- 
min, or  any  other  supposititious  compound. 

SANITARY  APPLICATIONS. 

Judgment  upon  the  analytic  results  from  a  given  sam- 
ple of  water  depends  upon  the  class  to  which  it  belongs, 
and  to  the  particular  influences  to  which  it  has  been  sub- 
jected. A  proportion  of  total  solids  which  would  be  sus- 
picious in  a  rain  or  river  water,  would  be  without  signifi- 


SANITARY   APPLICATIONS.  9! 

cance  in  that  from  an  artesian  well.  On  the  other  hand,  a 
subsoil  water  of  unobjectionable  character  would  contain  a 
proportion  of  nitrates  which  would  be  inadmissible  in  the 
case  of  a  river  or  deep  water.  Location  has  also  much 
bearing  in  the  case;  subsoil  waters  near  the  sea  will  be 
found  to  contain,  without  invoking  suspicion,  proportions 
of  chlorin  which  would  be  ample  to  condemn  the  same 
sample  if  derived  from  a  point  far  inland.  Hence  the  im- 
portance of  recording,  at  the  time  of  collection,  all  ascer- 
tainable  information  as  to  the  surroundings  and  probable 
source  of  the  water. 

Analyses  of  surface-waters  have  little  value,  unless  supple- 
mented by  a  careful  survey  of  the  watershed  to  determine 
sources  of  pollution.  Such  survey  will  often  discover 
conditions  sufficient  to  condemn  the  supply,  even  though 
the  analyses  may  be  satisfactory.  Indeed,  it  may  be  taken 
as  a  fundamental  principle,  that  no  water-supply  derived 
from  streams  flowing  through  a  populated  district  will  be 
safe  for  use  unless  efficiently  filtered. 

Color,  Odor,  and  Taste.— Water  of  the  highest 
purity  will  be  clear,  colorless,  odorless,  and  nearly  tasteless. 
While  in  some  cases  a  decided  departure  from  this  stand- 
ard may  give  rise  to  suspicion,  analytic  observations  are 
necessary  to  decide  the  point.  Water  highly  charged 
with  mineral  matters  will  possess  decided  taste,  vegetable 
matters  may  communicate  distinct  color ;  but,  on  the 
other  hand,  it  may  be  highly  contaminated  with  dangerous 
substances  and  give  no  indications  to  the  senses.  Well- 
waters  occasionally  become  offensive  in  odor,  from  pene- 
tration of  tree  roots.  The  odor  often  recalls  that  of 
hydrogen  sulphid.  Sulphids  are,  indeed,  often  formed  in 
such  cases  by  the  abstraction  of  oxygen  from  sulphates 


92  INTERPRETATION   OF   RESULTS. 

under  the  influence  of  microbes.  Such  waters  are  often 
used  without  apparent  injury,  but  it  is  probable  that  if 
direct  pollution  occurs,  the  danger  would  be  enhanced  by 
the  presence  of  the  vegetable  matter.  Miquel  has  de- 
scribed a  bacillus,  under  the  name  B.  sulphydrogenus, 
which  produces  hydrogen  sulphid  readily.  Some  of  the 
common  putrefactive  bacilli  doubtless  have  this  power 
also,  largely  through  the  influence  of  the  hydrogen  lib- 
erated by  them.  In  waters  containing  hydrogen  sulphid, 
species  of  beggiatoa,  especially  B.  alba,  thrive,  and 
decomposing  the  sulphid,  become  impregnated  with  sul- 
phur. Natural  sulphur  waters  frequently  contain  these 
organisms,  as  do,  also,  waste-waters  containing  sulphid. 

Surface  waters  collected  in  reservoirs  or  ponds  often 
become  very  offensive  from  the  growth  of  algae,  but  apart 
from  the  disgust  created  by  the  water  it  is  not  known  that 
any  harmful  results  occur  to  those  using  it. 

Turbidity  may  be  due  to  several  causes,  of  different 
degrees  of  danger,  but  is  always  objectionable. 

Total  Solids. — Excessive  proportions  of  mineral 
solids,  especially  of  marked  physiological  action,  are 
known  to  render  water  non-potable,  but  no  absolute  max- 
imum or  minimum  can  be  assigned  as  the  limit  of  safety. 
Distilled  water  and  waters  very  highly  charged  with  min- 
eral matter  have  been  used  for  long  periods  without  ill 
effects.  The  popular  notion  that  the  so-called  hard  waters 
conduce  to  the  formation  of  urinary  calculi  is  not  borne 
out  by  surgical  experience  nor  statistical  inquiry.  Many 
urinary  calculi  are  composed  of  uric  acid,  and  are  the 
results  of  disorders  of  the  general  nutritive  functions. 

Sanitary  authorities  have  fixed  an  arbitrary  limit  of  total 
solids  of  about  six  hundred  parts  per  million,  but  many 


SANITARY   APPLICATIONS.  93 

artesian  waters  in  constant  use  exceed  this.  An  instance 
is  found  in  the  well  on  Black's  Island,  near  Philadelphia, 
given  in  the  table  of  analyses,  which  contains  nearly 
twelve  hundred  parts  per  million,  is  very  agreeable  in 
taste,  and  has  been  in  constant  use  for  some  years  by  a 
number  of  persons  without  injury.  The  assertion  that  water 
to  be  wholesome  must  .contain  an  appreciable  proportion 
of  total  solids  is  also  not  demonstrated  by  clinical  expe- 
rience. A  discussion  of  the  effects  of  special  mineral 
ingredients,  e.  g.,  magnesium  sulphate,  ferrous  carbonate, 
etc.,  belongs  to  general  therapeutics. 

The  odor  produced  on  heating  the  water  residue  is  often 
of  much  use  in  detecting  contamination.  Odors  similar 
to  those  produced  by  heating  glue,  hair,  rancid  fats,  urine, 
or  other  animal  products,  will  give  rise  to  grave  suspicion. 
On  the  other  hand,  a  more  favorable  judgment  may  be 
given  when  the  odor  recalls  those  given  off  in  the  heating 
of  non-nitrogenous  vegetable  materials,  such  as  wood-fibre. 

Poisonous  Metals. — The  proportion  of  iron  in  water 
constantly  used  for  drinking  purposes  should  not  much 
exceed  three  parts  per  million.  Lead,  copper,  arsenum, 
and  zinc  must  be  considered  dangerous  in  any  amount, 
though  it  appears  that  zinc  and  copper,  being  least  cumu- 
lative, are  rather  less  objectionable  in  minute  amount  than 
the  others.  Concerning  the  limit  of  safety  with  mangan- 
ese and  chromium  very  little  is  known,  buf  their  presence 
in  appreciable  quantity  must  be  looked  upon  with  suspicion. 

Chlorids  and  Phosphates. — Chlorids — principally 
sodium  chlorid — and  phosphates  are  abundantly  distrib- 
uted in  rocks  and  soils,  and  find  their  way  into  natural 
waters ;  but  while  the  former  are  freely  soluble,  and  remain 
in  undiminished  amount  under  all  conditions  to  which  the 


94  INTERPRETATION    OF    RESULTS. 

water  is  subjected,  all  but  minute  amounts  of  the  latter 
are  either  precipitated  or  removed  by  the  action  of  living 
organisms.  Surface  and  subsoil  waters  ordinarily  contain 
but  a  few  parts  per  million.  Both  chlorids  and  phos- 
phates being  constant  and  characteristic  ingredients  of 
animal  excretions,  it  is  obvious  that  an  excess  of  them  in 
natural  waters,  unless  otherwise  accounted  for,  will  suggest 
direct  contamination.  Proximity  to  localities  in  which 
sodium  chlorid  is  abundant,  such  as  the  sea  or  salt  de- 
posits, will  deprive  the  figure  for  the  chlorin  of  diagnostic 
value,  nor  can  any  indication  of  sewage  or  other  danger- 
ous pollution  be  inferred  from  high  proportion  of  chlorin 
in  deep  waters.  Further,  it  has  been  shown  that  the  pro- 
portion of  chlorin  in  uncon laminated  waters  is  tolerably 
constant,  while  in  water  subjected  to  the  infiltration  of 
sewage  the  chlorin  undergoes  marked  variation  in  amount. 
In  most  cases,  therefore,  a  correct  judgment  can  only  be 
attained  by  comparison  with  the  average  character  of  the 
waters  of  the  same  type  in  the  district,  and  by  examination 
at  intervals  of  the  water  in  question. 

As  regards  phosphates,  Hehner,  who  has  published  a 
series  of  analyses,  states  that  the  presence  of  more  than  0.6 
parts  per  million — calculated  as  PO4 — should  be  regarded 
with  suspicion.  On  the  other  hand,  the  absence  of  phos- 
phates affords  no  positive  proof  of  the  freedom  from  pollu- 
tion. 

Nitrogen  from  Ammonium  Compounds. — Ammo- 
nium compounds  are  usually  the  results  of  the  putrefactive 
fermentation  of  nitrogenous  organic  matter ;  they  may  also 
be  the  product  of  the  reduction  of  nitrites  and  nitrates 
in  presence  of  excess  of  organic  matter.  In  either  case, 
therefore,  they  suggest  contamination.  Deep  waters  often 


SANITARY   APPLICATIONS.  95 

contain  an  excess  of  ammonium  compounds,  derived,  in 
large  part,  from  the  reduction  of  nitrates.  Their  presence 
here  is  hardly  ground  for  adverse  judgment,  since  the 
water,  even  though  originally  contaminated,  has  undergone 
extensive  filtration  and  oxidation,  its  organic  matter  con- 
verted into  bodies  presumably  harmless,  and  microbes  have 
perished.  Such  waters,  indeed,  usually  show  only  traces 
of  unchanged  organic  matter. 

Rain  water  often  contains  large  proportions  of  ammo- 
nium compounds ;  but  here,  also,  the  fact  cannot  condemn 
the  water,  since  it  does  not  indicate  contamination  with 
dangerous  organic  matter. 

The  evolution  of  ammonia  in  the  distillation  of  rain  water 
often  continues  indefinitely,  the  larger  portion  passing  over 
in  the  first  distillates,  but  small  quantities  being  present 
even  after  the  distillation  has  been  much  prolonged.  The 
same  continuous  evolution  of  ammonia  is  noted  in  waters 
containing  urea,  but  in  this  case  a  larger  proportion  is 
collected  in  the  earlier  distillates,  nearly  all  coming  over 
before  one-half  the  water  has  been  distilled.  Fox  gives  the 
following  figures  as  ratios  obtained  in  the  analysis  of  two 
samples,  one  of  rain  water  collected  from  a  roof  and  there- 
fore impure,  and  the  other  of  a  water  containing  urine : — 


Rain  Water. 

Urine  Water. 

ist  distillate  

•35 

•38 

parts  per  million. 

2d        "         .... 

•25 

.14 

"                 " 

3d         "         .... 

.12 

.065 

« 

4th       "         .... 

.09 

•°35 

.<                 « 

5th       «         .... 

.09 

"                 " 

6th       "        .... 

•04 

"                » 

7th       «        .... 

•03 

" 

.97  .620 


96  INTERPRETATION    OF    RESULTS. 

Nitrogen  by  Alkaline  Permanganate  (Nitrogen  of 
"albuminoid  ammonia  "). — A  large  yield  of  ammonia  by 
boiling  with  alkaline  potassium  permanganate  will,  of 
course,  point  to  an  excess  of  nitrogenous  organic  matter. 
The  inferences  to  be  drawn  depend  upon  the  origin  and 
condition  of  the  organic  material.  If  animal,  the  water 
may  at  once  be  condemned  as  unsafe.  Waters  containing 
excessive  amounts  even  of  vegetable  matter  are  not  free 
from  objection,  since  they  have  frequently  caused  persistent 
diarrhea.  If  the  organic  matter,  whether  animal  or 
vegetable,  is  in  a  state  of  active  decomposition,  it  is 
doubly  objectionable.  Mallet  has  called  attention  to  the 
fact  that  such  waters,  as  a  rule,  yield  ammonia  rapidly, 
whereas  non-decomposing  material  yields  it  but  slowly,  and 
he  points  out  the  importance,  therefore,  of  noting  the  rate 
at  which  the  ammonia  collects  in  the  distillate. 

Dr.  Smart  has  observed  that  water  containing  fermenting 
vegetable  matter  is  colored  yellow  by  boiling  with  sodium 
carbonate,  and  that  when  Nessler  reagent  is  added  to  the 
distillate,  a  greenish,  in  place  of  the  ordinary  yellowish- 
brown  color  is  produced.  He  applies  this  fact  in  con- 
junction with  the  determination  of  the  oxygen-consuming 
power  (Tidy's  process)  and  the  rate  of  evolution  of  the 
ammonia  by  alkaline  permanganate  as  follows  : — 

A  water  yielding  ammonia  slowly  by  alkaline  perman- 
ganate, contains  recent  organic  matter ;  of  animal  deriva- 
tion, if  the  oxygen-consuming  power  is  low;  of  vegetable, 
if  high. 

A  water  yielding  ammonia  more  rapidly  by  alkaline 
permanganate,  shows  decomposing  organic  matter;  of 
animal  origin,  if  the  oxygen-consuming  power  be  low  and 
there  be  no  interference  with  the  Nessler  reaction ;  of 


SANITARY   APPLICATIONS.  97 

vegetable  origin,  if  the  oxygen  consumed  be  high,  and  if 
a  yellow  color  be  produced  in  the  water  by  sodium  car- 
bonate, and  a  greenish  color  in  the  nesslerized  distillate. 

Inferences  as  to  the  source  of  the  organic  matter  can 
usually  be  drawn  from  the  amount  of  chlorin  and  nitrates 
present.  If  the  chlorin  be  high,  /.  e.,  in  excess  of  the 
average  of  the  district,  it  may  be  inferred  that  the  material 
is,  in  great  part,  of  animal  origin.  In  this  case  the 
nitrates  will  either  be  high  or  entirely  absent,  according  as 
the  contaminating  matter  has  passed  through  soil  or  enters 
the  water  directly. 

A  large  amount  of  vegetable  matter  will,  as  a  rule,  show 
itself  by  the  color  it  imparts  to  the  water. 

Wanklyn  gives  the  following  standards  : — 

High  purity, oo    to  .041  per  million. 

Satisfactory  purity, 041  to  .082    "         " 

Impure, over  .082. 

In  the  absence  of  ammonium  compounds,  he  does  not 
condemn  a  water  unless  the  nitrogen  by  permanganate  ex- 
ceeds .081  per  million;  but  a  water  yielding  0.123  parts 
per  million  of  nitrogen  by  permanganate  he  condemns 
under  all  circumstances. 

Total  Nitrogen. — Drown  and  Martin's  results  with 
surface  waters  indicate  that  the  total  nitrogen  obtained  by 
their  process  is  about  twice  that  obtained  by  alkaline  per- 
manganate. The  experiments  made  by  Dr.  Beam  and  my- 
self accord  with  this.  Further  observation  on  different 
waters  and  by  different  observers  will  be  required  to  de- 
termine the  value  to  be  assigned  to  the  figures  obtained 
by  this  method.  This  method  is  especially  suitable  for 
studying  the  effects  of  filtration,  storage,  etc.,  on  the  nitro- 
genous organic  matter  in  water. 
G 


98  INTERPRETATION   OF   RESULTS. 

Nitrogen  as  Nitrites. — Nitrites  are  present  in  water 
as  the  result  either  of  incomplete  nitrification  of  ammonium, 
or  the  reduction  of  already  formed  nitrates,  under  the  in- 
fluence of  reducing  agents  or  microbes.  Since  they  are 
transition  products,  their  presence  in  water  is  usually 
evidence  of  existing  fermentative  changes,  and,  further, 
may  be  taken  as  indicating  that  the  water  is  unable  to 
dispose  of  the  organic  contamination.  When,  however, 
the  conditions  are  such  that  oxidation  cannot  take  place, 
nitrites  may  persist  for  a  long  time.  This  sometimes 
occurs  in  deep  waters  in  which  fermentative  changes  have 
long  since  ceased,  but  oxygen  is  not  available.  These 
contain  not  infrequently  small  amounts  of  nitrites,  to 
which  the  same  degree  of  suspicion  cannot  be  attached. 
When  nitrites  are  found  in  these  waters,  the  possibility  of 
their  introduction  from  polluted  subsoil  water,  through 
defective  tubing,  must  not  be  overlooked.  Rain  water, 
also,  sometimes  contains  nitrites  derived  from  the  air, 
and  therefore  not  indicative  of  any  putrefactive  change. 
The  presence  of  measurable  quantities  of  nitrites  in  river 
or  subsoil  water  is  sufficient  ground  for  condemnation. 

Nitrogen  as  Nitrates. — Nitrates  are  the  final  point 
in  the  oxidation  of  nitrogenous  organic  matter,  especially 
animal  matters.  Rain  water  and  that  from  mountain 
streams  and  deep  wells,  except  from  cretaceous  strata, 
generally  contain  only  traces,  but  river  and  subsoil  waters 
will  always  contain  appreciable  amounts,  unless  some  re- 
ducing action,  such  as  recent  sewage-pollution,  is  at  work. 
When,  therefore,  a  water  contains  enough  mineral  matter 
to  demonstrate  its  percolation  through  soil,  and  at  the 
same  time  is  free  from  nitrates  or  contains  only  traces,  the 
occurrence  of  a  destructive  fermentation  may  be  inferred. 


SANITARY   APPLICATIONS.  99 

These  cases  are  not  uncommon  among  well-waters,  and 
the  samples  are  generally  turbid  from  suspended  organic 
matter.  Decided  departure,  either  by  increase  or  de- 
crease, from  the  proportion  of  nitrates  usual  in  the  same 
class  of  water  in  any  district  may  be  taken  as  evidence  of 
contamination. 

Oxygen-consuming  Power. — Sanitary  authorities 
differ  very  much  as  to  the  significance  of  this  datum.  At- 
tempts have  been  made  to  fix  maximum  limits  for  the  vari- 
ous types  of  water,  and  also  to  gauge  the  character  and 
condition  of  the  organic  matter  by  observing  the  rate  at 
which  the  oxidation  takes  place,  but  no  positive  conclu- 
sions can  be  given.  In  general,  it  may  be  said  that  a 
sample  which  has  high  oxygen-consuming  power  will  be 
more  likely  to  be  unwholesome  than  one  which  is  low  in 
this  respect  ]  but  the  interferences  are  so  numerous,  and 
the  susceptibility  to  oxidation  of  different  organic  matters 
of  even  the  same  type,  is  so  different,  that  the  method  is  at 
best  only  of  accessory  value.  It  is  especially  suitable  for 
consecutive  determinations  on  the  same  supply. 

The  following  proportions  are  given  by  Frankland  and 
Tidy  as  the  basis  of  interpreting  the  results  of  this 
method  : — 

Oxygen  Absorbed  in  Three  Hours. 

High  organic  purity, 05          parts  per  million. 

Medium  purity, 0.5  to  1.5     "     "         " 

Doubtful 1.5  to  2.1     «     "         « 

Impure,   ........  over  2.1  "     "         " 

For  the  method  with  acidified  permanganate  at  the  boil- 
ing heat,  the  German  chemists,  who  employ  it  largely,  re- 
gard an  absorption  of  2.5  parts  of  oxygen  per  million 
as  suspicious,  and  some  sanitary  authorities  have  fixed 


100  INTERPRETATION  OF  RESULTS. 

3.8  parts  of  oxygen  per  million  as  the  highest  permissible 
limit. 

Dissolved  Oxygen. — Full  aeration  of  water  is  favor- 
able to  the  destruction  of  organic  matter ;  a  decided  dimi- 
nution in  the  quantity  of  dissolved  oxygen  may  show  excess 
of  such  matter  and  of  microbic  life.  Gerardin  has  pointed 
out  that  this  diminution  is  associated  with  the  development 
of  low  forms  of  vegetable  life,  and  Leeds  has  recorded 
similar  facts.  These  changes  are  more  likely  to  take  place 
in  still  waters,  and  are  frequently  accompanied  by  disagree- 
able odor  and  taste.  In  cases  in  which  stored  waters  be- 
come unpalatable,  these  facts  should  be  borne  in  mind. 

Dupr6  has  given  the  following  as  the  basis  for  interpret- 
ing the  results  of  his  adaptation  of  the  determination  of 
dissolved  oxygen  : — 

"  A  water  which  does  not  diminish  in  its  degree  of  aera- 
tion during  a  given  period,  may  or  may  not  contain  organic 
matter,  but  presumably  does  not  contain  growing  organ- 
isms. Such  organic  matter  as  it  may  be  found  to  contain 
by  chemic  analysis  need  not  be  considered  as  dangerous 
impurity." 

"A  water  which  by  itself,  or  after  the  addition  of  gela- 
tin or  other  appropriate  cultivating  matter,  consumes  oxy- 
gen from  the  dissolved  air,  at  lower  temperatures,  but  does 
not  consume  any  after  heating  for,  say,  three  hours  at 
140°  F.,  may  be  regarded  as  having  contained  living  or- 
ganisms, but  none  of  a  kind  able  to  survive  exposure  to 
that  temperature." 

"  A  water  which  by  itself,  or  after  addition  of  gelatin 
or  the  like,  continues  to  absorb  oxygen  from  the  contained 
air  after  heating  to  140°  F.,  may  be  taken  as  containing 
spores  or  germs  able  to  survive  that  temperature." 


SANITARY    APPLICATIONS. 


Hardness.— The  degree  of  hardness  has  but  little  bear- 
ing on  the  sanitary  value  of  water,  but  is  important  in 
reference  to  its  use  for  general  household  purposes,  in  view 
of  the  soap-destroying  power  which  hard  waters  possess. 


USUAL   ANALYTIC   RESULTS   FROM    UNCON- 

TAMINATED   WATERS. 

Milligrams  per  Liter. 


Surface. 

Subsoil. 

Deep. 

Total  solids, 

5  to  20 

15  upward 

30  upward 

45  upward 

Chlorin,     . 
Nitrogen  by 
"         as 

permanganate, 
NH4(         .    .   ! 

.08  to  .20 
.20  to  .50 

.05  to  ,15 

.05  to  .10 
.00  to  .03 

quantity 
.03  to  .10 
Generally  high 

« 

nitrites,     .    .    . 

None  or 

None 

None 

None  or  traces 

"          " 

nitrates,     .    .    . 

Traces. 

.75  to  1.25 

1.5105 

.00103 

Inferences  from  Culture-Methods. — Owing  to  the 
great  differences  in  the  conditions  and  manner  of  growth 
in  various  species  of  microbes,  the  inferences  to  be  drawn 
from  the  cultivation  of  the  germs  present  in  a  water-sample 
are  uncertain.  In  spite  of  the  study  which  has  been  given 
to  the  subject,  the  differentiation  of  specific  forms  has  not 
reached  exactness,  nor  have  the  conditions  most  favorable 
to  growth  been  ascertained.  Different  observers  pursue 
different  methods  of  culture,  and  the  results  are  not  com- 
parable. Broadly  speaking,  the  examination  of  the  bacte- 
rial life  in  water  may  include  two  inquiries, — a  simple  cal- 
culation of  the  number  of  individual  living  microbes,  and 
the  detection  of  the  presence  of  certain  specific  forms. 
Even  the  first  of  these  objects,  though  simple,  cannot  be 
carried  out  with  absolute  certainty  at  the  present  day.  The 
number  of  microbes  in  water  is  subject  to  rapid  increase 


102  INTERPRETATION  OF  RESULTS. 

for  a  brief  period  after  collection  of  a  sample,  and  may 
be  greatly  modified  by  incidental  conditions  during  stor- 
age or  transportation,  so  that  little  value  can  be  attached  to 
quantitive  determination,  except  when  made  promptly. 
The  culture-fluids  ordinarily  used,  and  the  conditions  in 
which  the  culture  takes  place,  do  not  suffice  for  the  devel- 
opment of  all  the  forms  present.  The  cultivation  ought 
to  be  extended  over  many  days,  and  samples  of  the  water 
tried  with  various  nutritive  media  and  at  different  tempera- 
tures to  secure  a  knowledge  of  the  forms  present.  As  an 
indication  of  the  insufficiency  of  the  common  methods, 
it  may  be  mentioned  that  Miller  describes  six  species  of 
microbes  occurring  in  the  human  mouth,  none  of  which 
would  grow  on  any  form  of  culture-medium  which  he 
was  able  to  produce. 

It  is  necessary  that  any  record  of  bacteriologic  examina- 
tion of  water  should  include  a  precise  statement  of  the 
conditions  of  cultivation.  That  is,  composition  of  the 
culture-medium ;  if  alkaline  or  acid,  the  degree  of  this 
reaction  expressed  in  terms  of  some  standard  solution  ;  the 
temperature  at  which  the  cultivation  takes  place,  and  the 
time.  It  is  not  correct  to  record  the  number  of  individual 
colonies  observed  on  the  culture-field  as  indicative  of  so 
many  living  microbes,  for  in  some  cases  two  or  more 
microbes  may  have  been  jointly  concerned  in  the  formation 
of  a  colony.  A  proper  method  is  simply  to  enter  the 
observation  as  so  many  points  of  microbic  life,  and  to  add 
whatever  detailed  description  is  necessary.  Efforts  have 
lately  been  made  to  secure  a  consensus  of  opinion  among 
bacteriologists  as  to  the  most  satisfactory  method  of 
microbe-counting,  and  to  adopt  this  as  a  uniform  system, 
in  order  that  results  in  some  degree  comparable  may  be 


SANITARY   APPLICATIONS.  103 

obtained  by  different  observers.  At  a  convention  held 
under  the  auspices  of  the  American  Public  Health  Associ- 
ation in  New  York  City,  June  2ist  and  2 ad,  1895,  the 
first  step  in  this  direction  was  taken,  but  the  methods  are 
not  yet  sufficiently  developed  to  be  inserted. 

In  the  determination  of  specific  forms  far  greater  diffi- 
culty arises,  and  unfortunately  this  difficulty  concerns 
especially  the  great  problem  which  is  presented  to  the 
sanitary  chemist,  namely,  whether  a  given  water-supply  is 
likely  to  produce  disease.  The  recognition  of  so  charac- 
teristic a  form  as  the  comma-bacillus  in  water  is  not  very 
difficult,  but  it  is  a  problem  rarely  presented  to  those  chem- 
ists who  are  practicing  in  civilized  countries.  The  history 
of  the  attempts  to  determine  bacilli  of  objectionable  char- 
acter in  water  has  presented  a  continuous  evolution,  in 
which  a  degree  of  confidence  existing  at  one  time  has  been 
overturned  by  later  discoveries.  It  was  first  thought  that  a 
distinction  might  be  made  between  ordinary  water-bacteria 
and  sewage-bacteria,  by  reason  of  the  action  of  the  latter 
upon  the  gelatin  culture-medium.  Some  bacteria  grow 
without  altering  the  condition  of  the  gelatin  visibly ;  others 
rapidly  digest  it  and  produce  a  liquid  peptone.  It  was 
supposed  that  these  latter  were  the  more  objectionable 
forms,  and  some  chemists  still  record  the  liquefying 
microbes  as  "  sewage  microbes."  This  distinction  is,  how- 
ever, untenable.  Several  bacilli  known  to  be  associated 
with  intestinal  discharges  do  not  produce  any  liquefaction, 
while  some  that  are  harmless  rapidly  liquefy. 

The  method  used  in  the  Hygienic  Laboratory  of  the 
University  of  Michigan  has  the  sanction  of  high  authority 
and  the  benefit  of  extended  experience,  but  it  is  doubtful 
if  it  meets  the  requirements  of  the  sanitary  chemist. 


104  INTERPRETATION    OF   RESULTS. 

However  general  the  acceptance  of  the  method  by  physi- 
ologists, it  cannot  be  considered  safe  to  infer  that  germs 
which  are  poisonous  when  injected  subcutaneously  or  intra- 
abdominally  into  rats,  guinea-pigs,  rabbits,  and  mice,  are 
necessarily  dangerous  in  water  consumed  in  the  ordinary 
way  by  human  beings.  Tests  of  this  kind  require  the  very 
highest  skill  and  facilities,  involve  great  expense  and  delay  ; 
and  it  is  probable  that  in  a  large  majority  of  cases  a  careful 
analysis  upon  the  lines  generally  accepted  will  afford  as  safe 
a  ground  for  inference  as  this  elaborate  method.  It  is  not 
impossible  that  treatment  at  blood-heat  and  in  a  highly 
stimulating  nutritive  medium  may  materially  increase  the 
virulence  of  some  microbes. 

There  is,  however,  one  field  of  inquiry  in  which  even 
mere  microbe-counting  has  value,  and  that  is  in  comparing 
samples  of  the  same  water  before  and  after  some  treatment 
or  other  incident.  In  these  studies  the  method  is  suffi- 
ciently free  from  fallacy  to  make  the  results  trustworthy 
when  they  are  conducted  in  a  strictly  uniform  manner ; 
thus,  if  a  river-water  supplied  to  a  filter  be  studied  daily 
by  examination  of  repeated  samples  before  and  after  filtra- 
tion, inoculating  separate  portions  of  the  same  culture- 
medium,  and  multiplying  the  results  to  such  an  extent  as 
to  eliminate  accidental  differences,  a  comparison  between 
the  water  before  and  after  filtration  may  be  safely  made  as 
to  the  proportion  of  microbes  removed.  Moreover,  spe- 
cial microbes  of  highly  characteristic  properties  may  be 
introduced  in  large  quantities  into  the  water,  and  by  sub- 
sequent culture  the  extent  to  which  these  are  removed  may 
be  satisfactorily  recognized.  Thus  in  the  extended  ex- 
periments of  the  Massachusetts  State  Board  of  Health  the 
Bacillus  prodigiosus  was  employed  as  a  test-microbe,  its 


SANITARY   APPLICATIONS.  105 

chromogenic  power  enabling  it  to  be  detected  with  great 
facility.  It  is  said  in  these  reports  that  the  life-history  and 
habits  of  this  microbe  are  so  nearly  identical  with  that  of  the 
B.  lyphosus  that  it  is  conveniently  substituted  for  the  latter 
in  such  test  experiments.  Under  the  B.  typhosus  the 
Massachusetts  observers  refer  to  a  microbe  which  is 
obtained  from  blood  and  viscera  of  patients  dead  of 
typical  typhoid  fever.  Concerning  the  alleged  specific 
nature  of  this  microbe,  B.  typhosus,  or  B.  typhi-abdominalis, 
as  it  has  been  called  (the  latter  an  unfortunate  term  be- 
cause it  perpetuates  a  highly  inappropriate  name  for  ty- 
phoid-fever), it  must  be  noted  that  there  is  no  satisfactory 
evidence  as  to  the  existence  of  a  distinct,  differentiated, 
specific  form,  which  is  the  sole  and  only  cause  of  the  fever. 
The  old  method  of  recognizing  the  B.  typhosus,  by  culti- 
vation on  potato,  was  never  regarded  as  very  satisfactory, 
and  is  now  known  to  be  valueless.  Research  has  indicated 
that  several  common  water-bacteria  may  assume  temporary 
conditions,  known  as  "  involution-forms, v  in  which  they 
may  have  functions  different  from  those  ordinarily  belong- 
ing to  them.  Among  the  bacilli  that  seem  to  be  closely 
associated  with  those  forms  that  have  been  designated  as 
B.  typhosus,  is  one  which  is  extensively  present  in  the 
intestinal  contents  of  man  and  the  domestic  animals,  and 
which  is  designated  as  the  B.  coli-communis.  It  is  abun- 
dantly present  in  water  which  has  received  any  form  of 
sewage,  even  when  that  is  merely  surface- wash  ings.  It  is 
not  necessarily  associated  with  danger  to  those  drinking 
the  water,  but  its  presence  must  be  regarded  as  suspicious. 
It  has  undoubtedly  been  designated  as.Z?.  typhosus  in  many 
cases,  and  we  now  know  enough  of  the  errors  of  this  class 
of  investigation  to  say  positively  that  a  large  proportion 


106  INTERPRETATION  OF  RESULTS. 

of  the  earlier  literature  on  this  subject  is  without  value. 
Since  it  appears  that  B.  coli-communis  is  the  germ  most 
likely  to  be  confounded  with  the  specific  typhoid-causing 
germ,  if  such  exists,  the  efforts  of  observers  have  been 
directed  toward  indicating  the  specific  differences  as 
clearly  as  possible.  Unfortunately,  these  differences 
appear  to  be  entirely  negative  as  to  the  more  important 
form,  rendering  its  detection  in  the  presence  of  the  more 
positive  form  impossible.  Thus  it  is  said  that  the  B.  coli- 
communis  does  not  curdle  milk,  while  B.  typhosus  does. 
The  former  is  said  to  induce  fermentation  in  sugar- 
solutions,  and  to  furnish  the  indol-reaction  in  beef-peptone, 
while  the  latter  produces  neither  of  these  effects.  A 
French  observer,  however,  claims  that  by  growing  the  B. 
typhosus  under  new  conditions  the  reactions  of  the  B.  coli- 
communis  may  be  produced.  A  competent  American 
writer  has  recently  stated  that  "  between  what  we  may 
regard  as  typical  forms  of  the  B.  coli-communis,  on  the  one 
hand,  and  typical  forms  of  the  B.  typhosus,  on  the  other, 
there  is  a  whole  series  of  intestinal  bacilli  known  under 
various  names  and  described  by  various  bacteriologists, 
representing  a  perfect  gradation  from  one  microbe  to  the 
other."  Klein  states  that  the  true  typhoid-germ  produces 
an  iridescent  film  on  solid  gelatin  at  ordinary  temperatures 
after  a  few  days'  growth,  and  that  a  precipitate  is  formed 
in  melted  gelatin  at  37°  C.,  neither  of  which  actions  is 
exhibited  by  B.  coli-communis. 

Another  water-microbe  that  has  ordinarily  no  signifi- 
cance of  danger  is  the  B.  fluorescent  liquefaciens ,  but  the 
observations  of  Moore  (Bureau  of  Animal  Industry,  No. 
3),  show  that  cultures  of  this  microbe  suddenly  take  on 
septic  properties  and  lose  them  again  subsequently. 


ACTION    OF   WATER   ON   LEAD.  107 

Vaughan  {Amer.  Jour.  Med.  Set.,  August,  1892,  p.  198), 
has  expressed  himself  as  follows  in  regard  to  the  specificity 
of  B.  typhosus  : — 

"  Of  one  thing  I  am  certain,  and  that  is,  that  I  am 
ignorant  of  any  crucial  test,  or  of  any  combination  of 
tests,  upon  the  strength  of  which  I  can  say  at  present  that 
a  germ  which  I  may  find  in  drinking-water  is  identical  with 
the  so-called  typhoid  bacillus.  I  have  found  in  spleens, 
after  death  from  typhoid  fever,  germs  which  differ  from 
the  typhoid  bacillus  obtained  from  Berlin,  and  from  one 
another  as  markedly  as  my  B.  venenosus  differs  from  either 
or  both." 

ACTION  OF  WATER  ON  LEAD. 

The  almost  universal  use  of  lead  pipes  for  conveying 
water,  and  the  facility  with  which  some  waters  corrode 
and  dissolve  the  metal,  make  it  a  question  of  moment  to 
determine  the  cause  of  this  action  and  to  devise  means  for 
its  prevention.  The  subject  has  received  considerable 
attention  within  the  last  few  years,  and  the  conditions  which 
determine  corrosion  are  now  fairly  understood.  As  a  rule, 
it  is  found  that  waters  free  from  mineral  matter  dissolve 
lead  with  facility,  especially  in  the  presence  of  oxygen. 
Some  very  soft  waters  are  entirely  without  action,  and 
this  was  unexplained  until  a  few  years  ago,  when  Messrs. 
Crookes,  Odling,  and  Tidy  found  that  the  action  was  con- 
trolled by  the  amount  of  silica  contained  in  the  water. 
They  found  that  those  soft  waters  which,  when  taken  from 
the  service  pipes,  contained  a  notable  quantity  of  lead, 
gave,  on  the  average,  three  parts  of  silica  per  million  ;  in 
those  in  which  there  was  no  lead,  the  silica  present 
amounted  to  7.5  per  million,  and  in  those  in  which  the 


108  INTERPRETATION    OF   RESULTS. 

action  was  intermediate,  5.5  parts  per  million.  That  it 
was  really  the  silica  that  conditioned  the  corrosion,  was 
confirmed  by  laboratory  experiments.  They  also  found 
that  the  most  effective  way  of  silicating  a  water  is  by  passing 
it  over  a  mixture  of  flint  and  limestone.  The  reason  for 
this  was  pointed  out  later  by  Messrs.  Carnelly  and  Frew, 
who  showed  that  while  calcium  carbonate  and  silica  both 
exert  a  protective  influence,  calcium  silicate  is  more 
effective  than  either,  and,  further,  that  in  almost  all  cases 
in  which  corrosion  took  place  it  was  greater  in  the  presence 
of  oxygen.  This  is  particularly  the  case  with  potassium 
and  ammonium  nitrates  and  with  calcium  hydroxid.  The 
reverse  is  true  of  calcium  sulphate,  which  is  more  corrosive 
when  air  is  excluded.  Their  experiments  also  show  that 
the  presence  of  calcium  carbonate  or  calcium  silicate, 
altogether  prevents  corrosion  by  potassium  and  ammonium 
nitrates. 

As  the  result  of  an  elaborate  series  of  experiments,  Miil- 
ler  concludes,  that  while  chlorids,  nitrates,  and  sulphates 
all  act  upon  lead  pipes,  no  corrosion  takes  place  in  the 
presence  of  sodium  acid  carbonate,  and  that  calcium  car- 
bonate, by  taking  up  carbonic  acid,  acts  in  the  same  way. 
This  latter  conclusion  is  at  variance  with  the  observations 
of  Carnelly  and  Frew,  who  found  that  calcium  carbonate 
is  equally  effective  when  carbonic  acid  is  excluded.  Miil- 
ler  also  states  that  surface  waters,  contaminated  by  sewage 
and  containing  large  amounts  of  ammoniacal  compounds, 
will  dissolve  lead  under  all  circumstances. 

Allen  has  shown  that  water  containing  free  acid,  in- 
cluding sulphuric  acid,  acts  energetically  upon  lead.  This 
is  not  surprising  in  view  of  the  later  experiments,  which 
prove  that  even  calcium  sulphate  is  corrosive.  Later,  W. 


TECHNIC   APPLICATIONS.  109 

Carleton-Williams  found  that  even  in  the  presence  of  free 
acid,  corrosion  may  be  prevented  by  the  addition  of  suffi- 
cient silica.  His  experiments  also  confirm  the  view  gener- 
ally held,  that  soluble  phosphates  protect  lead  to  a  marked 
degree. 

The  following  is  a  summary  of  the  more  important  ob- 
servations on  this  subject  : — 

Corrosive  :  Free  acid  or  alkalies,  oxygen,  nitrates,  par- 
ticularly potassium  and  ammonium  nitrates,  chlorids,  and 
sulphates. 

Non-corrosive  and  preventing  corrosion  by  the  above  : 
Calcium  carbonate,  sodium  acid  carbonate,  ammonium 
carbonate,  calcium  silicate,  silica,  and  soluble  phosphates. 

It  is  said  that  filtration  through  animal  charcoal  is  a 
means  of  removing  the  greater  portion  of  any  lead  sus- 
pended or  dissolved  in  the  water.  Such  filters  must  be 
attended  to  and  renovated  from  time  to  time. 

TECHNIC  APPLICATIONS. 

Boiler  Waters. — The  main  conditions  affecting  the 
value  of  a  water  for  steam-making  purposes  are  its 
tendency  to  cause  corrosion  and  the  formation  of  scale. 
Corrosion  may  be  due  to  the  water  itself,  to  the  presence 
of  free  acids,  or  to  substances  which  form  acids  under  the 
influence  of  the  heat  to  which  the  water  is  subjected. 
Pure  water,  e.  g.,  distilled  water,  exhibits  a  powerfully 
corrosive  action  upon  iron.  The  dissolved  oxygen  which 
all  waters  contain  also  aids  in  the  corrosion,  and  especially 
when  accompanied,  as  is  usually  the  case,  by  carbonic 
acid.  There  is  always  greater  rusting  at  the  point  at 
which  the  water  enters  the  boiler,  since  there  the  gases  are 
driven  out  of  solution  and  immediately  attack  the  metal. 


110  INTERPRETATION  OF  RESULTS. 

This  is  an  evil  that  obtains  with  all  waters,  and  it  is  not 
customary,  in  making  examination  for  technical  purposes, 
to  determine  the  amount  of  these  bodies.  In  water  that 
has  had  free  access  to  air,  the  oxygen  in  solution  is  a 
tolerably  constant  quantity,  and  it  is  sufficient  to  note  the 
temperature  and  refer  to  the  table  of  amounts  of  oxygen 
dissolved  in  water.  The  corrosive  action  of  oxygen  and 
carbonic  acid  is  especially  noticeable  in  waters  that  are 
comparatively  pure,  such  as  those  derived  from  mountain 
springs.  This  was  repeatedly  observed  by  Dr.  William 
Beam,  in  the  examination  of  the  waters  used  for  the 
locomotives  of  the  Baltimore  and  Ohio  Railroad.  The 
waters  which  caused  the  most  corrosion  were  mainly  those 
containing  small  quantities  of  solid  matter,  the  full  amount 
of  oxygen  and  considerable  carbonic  acid,  but  no  other 
acid  or  acid-forming  body. 

Free  acid,  other  than  carbonic  acid,  is  not  often  found 
in  water,  and  if  present  renders  the  water  unfit  for  use, 
unless  it  be  neutralized.  Mine  waters  are  the  most  likely 
to  contain  free  acid,  sulphuric  acid  being  generally 
present.  Sometimes  the  acidity  is  due  to  organic  acids. 
These  act  very  injuriously  on  iron.  Allen  gives  an  ex- 
ample of  this  in  the  water  supplied  to  Sheffield,  Eng., 
which  he  found  to  contain  an  organic  acid  in  amount 
equivalent  to  from  3.5  to  10  parts  of  sulphuric  acid  per 
million. 

Magnesium  chlorid  is  frequently  present  in  waters,  and 
if  in  considerable  quantity  may  be  very  harmful.  At  a 
temperature  of  310°  F.,  corresponding  to  an  effective 
pressure  of  four  atmospheres,  magnesium  chlorid  reacts 
with  water  to  form  magnesium  oxid  and  hydrochloric  acid, 
the  latter  attacking  the  boiler,  especially  at  the  water  line. 


TECHNIC   APPLICATIONS.  Ill 

If  there  is  present  at  the  same  time  considerable  calcium 
carbonate  the  evil  may  be  somewhat  lessened,  but  as  Allen 
has  pointed  out,  and  as  we  also  have  noticed,  there  may 
still  be  corrosion,  so  that  the  presence  of  more  than  a  small 
quantity  of  the  salt,  say  a  grain  or  two  to  the  gallon,  may 
be  considered  objectionable.  Allen  remarks  that  the 
presence  of  a  certain  amount  of  sodium  chlorid  may 
prevent  this  decomposition,  the  two  chlorids  combining 
to  form  a  stable  double  salt.  The  addition,  therefore,  of 
common  salt  to  a  water  containing  magnesium  chlorid  may 
act  to  diminish  corrosion,  a  point  which  will  bear  further 
investigation. 

It  has  not  been  determined  how  far  the  presence  of 
nitrites,  nitrates,  and  ammonia  affects  the  quality  of  water 
for  steam-making  purposes ;  but  it  is  more  than  probable 
that  they  act  harmfully,  especially  the  nitrates,  which  are 
frequently  present  in  large  amount. 

Scale  is  composed  of  matters  deposited  from  the  water 
either  by  the  decompositions  induced  by  the  heat  or  by 
concentration.  When  the  deposit  is  loose  it  is  termed 
sludge  or  mud,  and  usually  consists  of  calcium  carbonate, 
magnesium  oxid  and  a  small  amount  of  magnesium  car- 
bonate. The  magnesium  oxid  is  formed  by  the  decompo- 
sition of  the  magnesium  carbonate  and  chlorid.  This  fact 
was  first  pointed  out  by  Driffield  (J.  Soc.  Chem.  Ind.,  vi, 
178). 

The  formation  of  sludge  is  the  least  objectionable  effect, 
since  it  may  readily  be  removed  by  "blowing  off,"  pro- 
vided that  care  is  previously  taken  to  allow  the  flues  to 
cool  down  so  that  when  the  water  is  removed  the  heat  of 
the  flues  may  not  bake  the  deposit  to  a  hard  mass.  Waters 
containing  calcium  sulphate  form  hard  incrustations  diffi- 


112  INTERPRETATION  OF  RESULTS. 

cult  to  remove  and  causing  great  loss  of  fuel  by  interfering 
with  the  transmission  of  the  heat  to  the  water.  It  not 
only  forms  a  hard  incrustation  in  itself,  but  becomes  in- 
corporated with  the  mud,  and  renders  it  also  hard.  The 
hard  scale  will  also  contain  practically  all  the  silica  and 
the  iron  and  aluminum  present  in  the  water,  besides  any 
matters  originally  held  in  suspension. 

It  follows  from  the  above  that  a  water  only  temporarily 
hard  will,  if  care  is  taken  in  the  management  of  the  boiler, 
cause  the  formation  merely  of  a  loose  deposit  of  sludge — 
temporary  hardness  being  due  in  the  main  to  calcium  and 
magnesium  carbonates.  A  water  permanently  hard  will 
probably  form  a  hard  scale,  since  such  hardness  is  usually 
due  to  calcium  sulphate. 

In  accordance  with  these  principles,  the  analysis  of  a 
water  for  steam-making  purposes  may  include  the  deter- 
minations of  free  acid,  total  solid  residue,  SO4,  Cl,  Ca,  Mg, 
temporary  and  permanent  hardness.  In  cases  in  which  the 
qualitative  tests  show  but  small  amounts  of  SO4  and  Cl, 
the  analysis  may  be  limited  to  the  determinations  of  the 
temporary  and  permanent  hardness. 

It  has  been  pointed  out  in  an  earlier  chapter  that  it  is 
not  possible  to  deduce  from  the  analytic  result  the  exact 
forms  in  which  the  various  elements  are  combined,  but 
since  it  is  known  that  at  the  high  temperature  ordinarily 
reached  in  boilers  definite  chemical  changes  occur,  it  is 
safest  to  exhibit  the  maximum  amount  of  corrosive  and 
scale-forming  ingredients  which  the  water  under  these  cir- 
cumstances could  develop.  Thus,  since  calcium  sulphate 
is  practically  insoluble  in  water  above  212°  F.,  the  pro- 
portion of  calcium  sulphate  may  be  regarded  as  such  as 
would  be  formed  by  the  total  quantity  of  calcium  or  the 


TECHNIC   APPLICATIONS.  113 

total  quantity  of  SO4,  according  to  which  is  present  in  the 
larger  amount.  Similarly,  as  the  decomposition  of  magne- 
sium chlorid  is  induced  by  the  high  temperature  of  the 
boiler,  the  analytic  statement  should  indicate  the  maxi- 
mum proportion  of  this  compound  obtainable  from  the 
magnesium  and  chlorin  present.  These  rules  cannot  apply 
absolutely  to  waters  rich  in  alkali-carbonates,  since  these 
would  neutralize  any  acid  formed  from  the  magnesium 
chlorid,  or  even  prevent  its  formation,  and  would  prevent 
to  a  large  extent  the  formation  of  calcium  sulphate.  Much 
remains  to  be  determined  concerning  the  effects  of  the 
high  temperature  and  concentration  to  which  boiler  waters 
are  subjected. 

General  Technic  Uses. — In  regard  to  the  quality 
of  water  for  technic  other  than  steam -making  purposes, 
such  as  brewing,  dyeing,  tanning,  etc.,  no  detailed  meth- 
ods or  standards  can  be  laid  down.  The  nearest  approach 
to  purity  that  can  be  secured  in  the  supply  will  be  of  the 
greatest  advantage.  The  more  objectionable  qualities  will 
be  large  proportion  of  organic  matter,  especially  if  it  dis- 
tinctly colors  the  water,  excessive  hardness,  and  notable 
amounts  of  iron  or  free  mineral  acid.  It  is  stated  by 
Bell  {Jour.  Soc.  Chem.  Ind.~}  that  one  part  per  million  of 
iron  will  render  water  unsuitable  for  bleaching  establish- 
ments. It  has  been  noted  that  a  large  proportion  of  active 
microbes  is  injurious  in  the  manufacture  of  indigo.  In 
artificial  ice  making,  a  very  pure  water  must  be  used  if 
a  clear  and  colorless  product  be  desired.  Any  suspended 
or  dissolved  coloring  matter  will  be  concentrated  by  the 
freezing  and  appear  in  the  bottom  or  center  of  the  mass. 
The  Antwerp  water,  purified  by  the  Anderson  process,  is 
H 


114  INTERPRETATION   OF   RESULTS. 

used  with  entire  satisfaction  for  the  manufacture  of  artifi- 
cial ice  in  that  city. 

The  examination  of  sewage- effluents  and  waste  waters 
from  manufacturing  establishments  is  to  be  conducted  upon 
the  same  principles  as  for  ordinary  supplies,  but  especial 
attention  must  be  given  to  the  presence  of  poisonous 
metals,  and  free  mineral  acids.  The  latter  interfere  with 
the  normal  self-purification  of  the  water.  For  the  nitro- 
gen determination,  the  Kjeldahl  process  will  be  found 
more  satisfactory  than  that  by  alkaline  permanganate. 

PURIFICATION  OF  DRINKING-WATER. 

The  most  obvious  method  of  purifying  water  is  by  dis- 
tillation. The  process  is  too  expensive  for  general  use,  but 
is  especially  adapted  for  water  intended  for  pharmaceutical 
or  chemical  purposes.  It  has  also  been  used  for  supplying 
vessels  at  sea  and  in  tropic  localities  in  which  the  natural 
waters  may  be  contaminated  with  malarial  or  other  germs. 
The  majority  of  microbes  are  killed  by  short  exposure  to  a 
temperature  of  212°  F. ;  hence,  water  may  be  purified,  on 
a  small  scale,  by  simple  boiling.  Freezing  does  not  have 
the  same  effect,  many  microbes  retaining  vitality  for  a  long 
while  in  ice. 

The  self-purification  of  water,  that  is  the  destruction  of 
organic  matter  and  pathogenic  microbes,  by  reason  of  the 
development  of  the  ordinary  microbes  of  putrefaction, 
occurs  satisfactorily  only  in  alkaline  waters,  hence,  acid 
effluents  check  this  process.  The  addition  of  lime  in  suffi- 
cient amount  to  give  a  slightly  alkaline  reaction  will  be 
beneficial. 

The  conditions  necessary  to  secure  self-purification  of 


PURIFICATION    OF    DRINKING-WATER.  115 

surface  waters  are  not  fully  understood,  and  it  is  unsafe  to 
state  that  a  polluted  stream  will  purify  itself  in  any  given 
distance.  It  must  also  be  remembered  that  the  dilution 
of  infected  sewage  by  its  introduction  into  a  large  volume 
of  uninfected  water  will  assist,  for  a  time,  at  least,  the 
multiplication  of  pathogenic  microbes. 

Heider  made  a  study  of  the  water  of  the  Danube.  Al- 
though there  is  not  complete  commingling  for  several 
miles  after  the  sewage  inflow,  yet,  as  soon  as  the  sewage  is 
diluted  somewhat  more  than  seven  times,  the  analytic  dif- 
ferences between  the  river  water  above  and  that  below  the 
contaminating  inflow  are  exceedingly  small,  yet  the  bacteria 
remain  several  times  as  numerous  for  miles  down  stream 
after  the  introduction  of  the  sewage-water.  Muscle-tissue 
stained  by  bile  was  found  after  the  water  had  flowed  for 
twenty-five  miles.  The  current  of  the  river  is  from  four  to 
seven  miles  an  hour.  Gruber  and  von  Kerner  have  shown 
that  cholera  germs  can  remain  alive  for  from  five  to  seven 
days  in  the  river-water,  as  also  in  the  Vienna  aqueduct- 
water.  Hence  the  self-purification  is  a  matter  of  dilution, 
and,  as  elsewhere,  should  not  be  relied  upon  when  epi- 
demics of  water-borne  infectious  diseases  are  present.  Pu- 
pils of  Pettenkofer  who  studied  the  Isar  water  at  Munich, 
consider  that  self-purification  within  twenty  miles  was  there 
more  reliable  and  certain.  Fraenkel  has  recently  found 
that  the  Lahn  purified  itself  speedily  after  the  sewage  of 
Marburg  entered  it. — (JV.  Y.  Med.Jour.,  Dec.  i,  1894.) 

The  methods  in  general  use  for  purifying  water  are 
simple  filtration  and  the  removal  of  the  impurities  by  ap- 
propriate chemical  agents. 

Filtration. — For  household  purposes  forms  of  carbon, 
stone  and  sand  filters  are  used,  which  yield  clear  filtrates, 


n6 


INTERPRETATION   OF   RESULTS. 


but  permit,  sooner  or  later,  the  transmission  of  microbes. 
The  suspended  matter  in  the  water  gradually  accumulates 
on  the  surface  of  the  filter,  and  causes  a  great  increase  in 
the  number  of  the  microbes,  some  species  of  which  appar- 
ently grow  through  the  pores  of  the  filter,  and  are  carried 
into  the  filtrate.  The  following  are  among  the  more 
efficient  forms  of  household  filters: — 

Bischof  Spongy-Iron  Filter, — The  construction  of  this  is 
shown  in  Fig.  TO.     The  spongy  iron  is  obtained  by  re- 
ducing hematite,  at  a  temperature 
FlG- I0-  below  the  fusing  point  of  iron. 

It  rests  on  a  layer  of  pyrolusite 
(manganese  dioxid),  below  which 
is  an  asbestos  bag  having  a  short 
tube  with  perforated  cap.  This  is 
a  very  efficient  form,  removing 
much  of  the  dissolved  organic  mat- 
ter, and  practically  all  the  sus- 
pended matter,  including  the  mi- 
crobes. 

Chamberlain-Pasteur  Filter.  — 
This  consists  of  tubes  of  unglazed 
biscuit-ware,  the  number  depending 
on  the  size  and  required  delivery 
of  the  filter.  There  are  arrange- 
ments for  continuous  filtration  by  attaching  the  tube  to  the 
faucet ;  also  forms  adapted  to  simultaneous  cooling  and 
filtration.  The  observations  of  Pasteur  and  others  have 
shown  that  this  is  a  highly  efficient  filter,  yielding  for  a 
considerable  time  a  filtrate  entirely  sterile.  It  requires 
occasional  cleaning,  since,  after  continuous  use,  the  mi- 
crobes may  pass  through  the  pores,  probably  by  a  process 


PURIFICATION    OF    DRINKING-WATER. 


of  growth.  An  occasional  boiling  of  the  tubes  in  water 
would  be  sufficient  to  overcome  this  difficulty. 

Fig.  ii  shows  a  form  of  sand  filter  which  is  used  in  the 
laboratory  of  Professor  Kemna,  at  Antwerp.  A  moderately 
wide  and  stout  tube  is 
passed  to  the  bottom  of  a 
tall  jar,  and  the  interven- 
ing space  filled  to  the  depth 
of  about  25  cm.  with  fine 
sand,  coarse  sand,  and 
gravel,  as  shown.  The 
exit  tube  consists  of  a 
siphon,  the  outer  leg  of 
which  does  not  quite  reach 
to  the  level  of  the  surface 
of  the  sand,  the  inner  leg 
reaching  to  the  bottom  of 

the  jar.  The  flow  may  be  controlled  by  a  stop-cock  at- 
tached to  the  outer  leg.  The  object  of  this  arrangement 
is  to  prevent  the  water-level  being  drawn  to  or  below  the 
level  of  the  sand.  The  filter  should  be  supplied  from  a 
reservoir  by  means  of  a  siphon,  the  exit  tube  of  which  is 
curved  upward,  in  order  to  prevent  disturbing  the  deposit 
which  collects  on  the  surface  of  the  filter. 

The  filter  may  be  cleaned  by  removing  the  siphon  and 
sending  a  slow  current  of  water  down  the  wide  tube  until 
the  deposit  upon  the  surface  of  the  sand  is  washed  out. 
The  apparatus  is  especially  suited  for  laboratory  experi- 
ments on  filtration. 

Many  other  forms  of  filter  have  been  devised.  Com- 
prehensive comparative  tests  made  under  the  auspices  of 
the  British  Medical  Journal  show  that,  except  as  to  those 


Il8  INTERPRETATION    OF   RESULTS. 

based  on  the  principle  of  the  Chamberlain-Pasteur  filter, 
but  little  time  elapses  before  the  filtrate  contains  numerous 
microbes. 

For  the  purification  of  drinking-water  on  a  large  scale, 
sand  filter-beds  have  been  found  to  be  efficient ;  but  the 
best  results  are  obtained  only  under  proper  supervision. 

Numerous  determinations  of  the  efficiency  of  sand  filter- 
ing basins  have  been  made  by  various  methods.  It  has 
been  found  that,  at  the  start,  a  large  proportion  of  the 
organic  matter,  dead  and  living,  passes  through ;  but  that 
as  filtration  proceeds,  the  surface  of  the  sand  becomes 
covered  with  a  close  deposit,  which  acts  both  as  a  means 
of  retaining  suspended  impurities  and,  by  its  active  micro- 
bic  life,  destroys  the  organic  matter  in  a  manner  analogous 
to  that  occurring  in  soil.  The  water  thus  becomes  prac- 
tically free  from  microbes,  but  after  a  time  these  gradu- 
ally penetrate  the  pores  of  the  filter  and  appear  in  the 
filtrate.  Increase  of  pressure  will  hasten  this  effect. 

Bertschinger  (Jour.  Soc.  Chem.  Ind.,  Dec.,  1889)  has 
published  observations  on  the  efficiency  of  the  sand  filters 
in  use  at  the  Zurich  Water-works.  The  filtering  material 
rests  on  a  brick  grating,  and  consists  of  the  following 
layers,  commencing  at  the  bottom  : — 

Five  to  15  cm.  of  coarse  gravel,  10  cm.  of  garden  gravel, 
15  cm.  of  coarse  sand  and  80  cm.  of  fine  sand.  As  soon 
as  the  diminution  in  pressure  of  water,  due  to  the  resistance 
of  the  filter,  is  from  60  to  80  cm.,  the  filter  is  cleaned  by 
allowing  the  water  to  run  off  and  removing  the  top  layer 
of  sand  to  a  depth  of  two  cm.,  as  this  is  found  to  contain 
the  whole  of  the  mud.  The  filter  is  then  filled  up  with 
filtered  water  from  below,  and  washed  by  allowing  this  to 
overflow.  After  filtration  has  recommenced,  the  first 


PURIFICATION   OF   DRINKING-WATER.  119 

portion  of  the  filtrate  is  rejected.  Two  of  the  filters  are 
arched  over ;  these  require  cleaning  once  in  seventy-seven 
days,  the  others  once  in  forty-eight  days.  As  soon  as  the 
layer  of  fine  sand  has  been  reduced  to  the  thickness  of  50 
cm.,  fresh  sand  is  substituted  or  more  added,  until  the 
depth  is  again  80  cm.  Among  the  conclusions  reached 
are  the  following  : — 

Under  normal  conditions  the  filtered  water  is  free  from 
microbes,  although  a  few  are  taken  up  again  in  the  later 
stages  of  the  filtration. 

After  cleaning  the  filter,  the  water  which  first  passes 
through  is  not  in  normal  condition.  It  contains  many 
microbes,  the  efficient  layer  of  scum  not  having  had  time 
to  collect  on  the  sand,  though  the  chemical  purity  of  the 
water  is  satisfactory. 

When  the  filters  have  not  been  used  for  some  time,  the 
water  which  first  passes  through  them  contains  more  bac- 
teria than  usual,  owing  to  their  rapid  multiplication  in 
stagnant  water,  but  its  chemical  purity  is  not  materially 
different  from  the  normal  filtered  water. 

Sand-filtration  has  been  brought  to  practical  use  at  Law- 
rence, Massachusetts,  where  a  filter  has  been  in  operation 
for  several  years,  with  the  effect  of  markedly  reducing  the 
death-rate  from  typhoid-fever  in  that  city.  The  water 
supplied  is  that  of  the  Merrimack  River,  which  ten  miles 
above  the  Lawrence  intake  receives  the  sewage  of  Lowell, 
a  town  of  80,000  population.  The  following  is  a  descrip- 
tion of  the  Lawrence  filter  given  by  Mr.  George  W.  Fuller, 
biologist  in  charge  of  the  Lawrence  Station.  It  was 
designed  by  Hiram  F.  Mills,  Engineer-member  of  the 
Massachusetts  State  Board  of  Health. 

It  is  2.5  acres  in  area,  and  contains  sand  of  an  average 


120  INTERPRETATION    OF    RESULTS. 

depth  of  about  4.5  feet.  The  depth  of  sand  varies  from 
three  to  five  feet,  but  owing  to  the  arrangement  of  the 
underdrains  all  water  passes  through  at  least  five  feet  of 
filtering  material.  The  filter  is  situated  by  the  side  of  the 
Merrimack  River,  and  separated  from  it  by  an  embank- 
ment. Its  surface  is  two  feet  below  low  water  in  the  river. 
The  water  is  allowed  to  flow  on  to  the  filter  about  16  hours 
a  day  on  an  average,  and  during  the  remainder  of  the  time 
the  sand  is  drained  and  the  pores  filled  with  air.  The 
filtered  water  is  conducted  by  underdrains  to  a  collecting 
conduit,  and  thence  to  the  pump-well.  The  pumps  deter- 
mine the  rate  of  filtration,  and  are  speeded  so  that  the 
water  shall  pass  through  the  filter  at  the  rate  of  2,000,000 
gallons  per  acre  per  day.  From  the  pumps  the  water 
passes  to  the  open  distributing  reservoir,  which  is  25  feet 
deep  at  high  water  and  contains  40,000,000  gallons.  The 
water  then  flows  by  gravity  from  the  reservoir  to  the  con- 
sumers. 

From  the  time  when  the  filter  was  put  in  operation,  Sep- 
tember 20,  1893,  until  May  i,  1894,  daily  bacteriologic 
tests,  in  addition  to  numerous  analyses,  were  made  of  the 
water  before  and  after  its  passage  through  the  filter,  as  it 
leaves  the  reservoir,  and  from  taps  at  the  City  Hall  and 
Experiment  Station,  which  are  distant  1.5  and  2.5  miles, 
respectively,  from  the  reservoir.  The  results  were  as  fol- 
lows: — 

Average  number  of   Percentage 
bacteria  in  one  c.c.       removed, 

River, 10,900  .    .    . 

Effluent  at  Filter, 264  97.58 

"  "  Reservoir  Outlet, 130  9&73 

"  "  City  Hall, 90  99. 17 

"  "  Experiment  Station,  ....  82  99-25 


PURIFICATION    OF    DRINKING-WATER.  121 

The  above  averages  include  all  results.  Excluding  those 
results  obtained  under  conditions  which  were  abnormal 
and  are  not  likely  to  occur  again,  we  find  that  this  filter 
normally  reduced  the  bacteria  from  9000  to  150  per  cubic 
centimeter,  a  removal  of  98.3  per  cent,  of  the  number 
applied.  Owing  to  the  fact  that  some  ground  water  of 
somewhat  unsatisfactory  quality  with  regard  to  numbers  of 
bacteria  was  at  times  mixed  with  the  effluent,  it  is  very 
improbable  that  all  the  bacteria  in  the  water  pumped  to  the 
reservoir  passed  through  the  filter. 

The  following  account  of  some  details  of  the  construc- 
tion of  filters  for  sewage-purification  has  been  furnished 
me  by  H.  W.  Clark,  Chemist  at  the  Massachusetts  Experi- 
ment Station,  Lawrence,  Mass.  :  The  sands  in  use  in  the 
large  filter  vary  in  effective  size  from  .04  mm.  to  1.40  mm. 
That  is  to  say,  the  finest  ten  per  cent,  of  the  material  is 
composed  entirely  of  grains  whose  diameter  is  less  than 
.04  mm.  in  the  finest  material  used,  and  less  than  1.40  mm. 
in  the  coarsest.  With  coarse  and  medium-fine  sand  a 
filter  contains  but  one  grade  throughout  the  entire  five 
feet.  With  fine  sands,  trenches  are  sometimes  dug  one 
to  two  feet  deep,  and  filled  with  coarser  sand.  This  gives 
a  given  area  greater  filtering  capacity.  With  what  is  con- 
sidered the  best  grade  of  sand  the  applied  dose  of  sewage, 
one  hundred  thousand  gallons  per  acre  per  day,  passes 
below  the  surface  of  the  sand  in  a  time  varying  from  ten 
minutes  to  one-and-a-half  hours,  depending  mainly  on  the 
condition  of  the  surface  of  the  filter.  The  remainder  of 
the  twenty-four  hours  the  surface  is  uncovered.  In  the 
intermittent  filtration  of  water  as  now  practiced  at  this 
station,  the  surface  of  the  filter  is  uncovered  two  hours  out 
of  the  twenty-four. 


122  '          INTERPRETATION  OF  RESULTS. 

The  liability  to  the  free  passage  of  microbes  for  a  short 
time  after  filter-cleaning  has  been  often  alleged  as  a  draw- 
back in  the  use  of  sand-filtration.  It  is  thought  that 
the  formation  of  a  close  film  of  microbes  upon  the  surface 
of  the  filter  is  necessary  to  perfect  working,  but  the  obser- 
vations at  Lawrence  have  indicated  that  this  period  of 
diminished  efficiency  is  due  in  part  to  the  mechanical 
disturbance  of  the  main  body  of  the  filtering  material, 
during  the  process  of  refilling  with  water  after  the  draining 
and  scraping.  Slowly  filling  the  filter  from  below  upward 
has  been  found  to  be  a  reliable  method  of  avoiding  the 
difficulty.  It  is  stated  by  Mr.  Fuller  that  a  much  greater 
speed  than  2,000,000  gallons  per  acre  per  day  can  be  em- 
ployed without  diminishing  the  efficiency  for  at  least  a  time, 
but  it  is  not  yet  known  how  this  will  affect  the  permanent 
efficiency  of  the  filter. 

Precipitation  Methods. — The  observations  of  Dr. 
P.  F.  Frankland  and  others  have  established  the  following 
points  : — 

"  Organized  matter  is,  to  a  large  and  sometimes  to  a  most 
remarkable  extent,  removable  from  water  by  agitation  with 
suitable  solids  in  a  fine  state  of  division,  but  such  methods 
of  purification  are  unreliable. 

"  Chemical  precipitation  is  attended  with  a  large  reduc- 
tion in  the  number  of  microorganisms  present  in  the  waters 
in  which  the  precipitate  is  made  to  form  and  allowed  to 
subside. 

"  If  subsidence  either  after  agitation  or  after  precipita- 
tion be  continued  too  long,  the  organisms  first  carried  down 
may  again  become  redistributed  throughout  the  water." 

It  is  essential,  therefore,  that  the  liquid  be  filtered  as 
short  a  time  after  the  precipitation  as  possible. 


PURIFICATION   OF   DRINKING-WATER.  123 

Precipitation  by  Aluminum  Compounds. — A  small  quantity 
of  aluminum  sulphate  added  to  natural  waters  is  decom- 
posed with  the  formation  of  a  flocculent  precipitate  of 
aluminum  hydroxid,  which  settles  comparatively  rapidly, 
and  carries  down  with  it  all  suspended  matters,  as  well  as 
a  large  proportion  of  the  dissolved  organic  matters. 
Waters  which  contain  such  an  excess  of  organic  matter  as 
to  be  distinctly  colored,  may  usually  be  made  quite  clear 
and  colorless  by  this  treatment.  One  grain  to  the  gallon 
will  suffice  for  the  purpose,  but  if  very  rapid  subsidence  is 
desired  more  may  be  added. 

This  precipitation  is  a  gradual  process,  and  a  water  that 
will  give  the  test  for  aluminum  immediately  after  filtering 
may  give  none  after  twenty-four  hours.  It  is  not  infre- 
quently noted  that  such  effluents,  originally  clear,  become 
cloudy  on  standing,  in  consequence  of  the  separation  of 
aluminum  hydroxid.  On  the  addition  of  aluminum  sul- 
phate to  brown  surface-waters  there  is  also  a  precipitation 
by  the  organic  matters.  A  sample  of  the  Cochituate-river 
water  (Boston  supply),  of  moderately  deep  color,  to  which 
25  milligrams  of  alum  to  the  liter  had  been  added,  when 
filtered  gave  no  reaction,  even  when  2.5  liters  were  con- 
centrated for  the  test.  An  addition  of  30  milligrams  to 
the  liter  could  be  detected  without  difficulty. 

Several  systems  of  filtration  now  in  extended  use  employ 
this  precipitation  method  in  conjunction  with  filters  of 
small  area,  the  necessary  flow  being  obtained  by  increased 
pressure.  The  differences  between  the  various  forms  are 
chiefly  in  the  mechanical  arrangements  for  supplying  the 
water  and  for  cleaning  the  filter.  The  material  is  generally 
sand  or  coke  ;  the  cleaning  is  performed  at  short  intervals, 


124  INTERPRETATION  OF  RESULTS. 

by  means  of  reverse  currents  of  water.     The  aluminum 
solution  is  introduced  as  needed  by  automatic  apparatus. 

These  filters  are  efficient,  and  are  suitable  for  the  purifi- 
cation of  water  for  manufacturing  establishments,  and  when 
large  basins  are  not  available. 

The  addition  of  an  iron  salt  to  water  containing  carbon- 
ates, is  attended  with  decomposition  and  the  formation  of 
a  precipitate  of  ferric  hydroxid.  This  reaction  has  been 
employed  with  great  advantage  as  a  means  of  purification. 
One  of  these  methods  was  by  passing  the  water  through 
spongy  iron,  then  aerating  to  precipitate  the  iron,  and  fil- 
tering through  sand.  The  method  is  very  efficient,  but  the 
spongy  iron  gradually  chokes  by  oxidation  and  becomes 
useless.  This  difficulty  is  removed  by  the  use  of  iron  bor- 
ings or  punchings,  contained  in  an  iron  cylinder  (Anderson 
and  Ogston,  Proc.  Inst.  Civ.  Eng.,Vo\.  81),  which  is  rotated 
while  the  water  passes  through ;  the  iron  is  brought  into 
thorough  contact  with  the  water,  and  there  is  sufficient 
abrasion  to  keep  its  surface  clean. 

The  apparatus  as  practically  employed  is  shown  in  Fig. 
12.  It  consists  of  a  cylinder  rotating  in  a  horizontal  position , 
attached  to  the  internal  periphery  of  which  are  short  curved 
shelves,  arranged  at  equal  distances.  Pipes  enter  the  hollow 
trunnions  to  admit  and  discharge  the  water.  As  it  enters 
the  cylinder,  the  water  strikes  against  a  circular  distributing 
plate,  and  is  caused  to  flow  radially  through  a  narrow  an- 
nular space,  to  prevent  the  formation  of  a  central  current 
along  the  axis  of  the  purifier.  The  inner  end  of  the  out- 
let pipe  carries  an  inverted  bell-mouth  which  catches  the 
fine  particles  of  the  iron  carried  forward  by  the  water, 


126  INTERPRETATION   OF   RESULTS. 

and  causes  them  to  fall  again  to  the  bottom  of  the  cylinder. 
Sufficient  borings  or  punchings  to  one-tenth  fill  the 
cylinder  are  introduced,  and  the  purifier  is  then  completely 
filled  with  water,  and  set  in  motion,  the  rate  of  rotation 
being  about  six  feet  per  minute  at  the  periphery.  The 
effect  of  the  rotation  is  to  scoop  up  the  iron  particles  and 
to  shower  them  down  through  the  flowing  water. 

The  effect  is  due  mainly  to  the  formation  of  ferrous 
carbonate,  through  the  action  of  the  carbonic  acid  of  the 
water.  On  issuing  into  the  open  air  this  is  gradually  con- 
verted by  oxidation  into  the  insoluble  ferric  hydroxid, 
which  carries  down  much  of  the  organic  matter  and  sub- 
sequently oxidizes  and  destroys  it.  Temporary  hardness 
is  also  decreased  by  the  abstraction  of  the  carbonic  acid 
and  -consequent  precipitation  of  calcium  and  magnesium 
carbonates. 

The  time  of  contact  with  the  iron  depends  upon  the 
purity  of  the  water.  For  Antwerp  water,  which  is  purified 
by  this  means,  the  maximum  effect  is  accomplished  in  3.5 
minutes.  After  leaving  the  cylinder,  the  water  is  passed 
through  sand  filters.  Analytic  examinations  show  the  effluent 
water  to  be  of  high  organic  purity  and  practically  sterile. 

Cast-iron  borings  are  much  more  readily  acted  upon 
than  steel  punchings.  The  latter  suffice  in  operating  upon 
water  rich  in  dissolved  organic  substances,  carbon  dioxid 
and  suspended  matters,  while  the  former  are  especially 
suited  for  treatment  of  water  comparatively  pure,  and, 
therefore,  less  active. 

For  determining  the  most  advantageous  method  of  treat- 
ing any  water  supply,  laboratory  experiments  may  be  made 
as  follows: — 

A  strong  wide-mouth  bottle  holding  about  2000  c.  c.,  is 


PURIFICATION    OF   DRINKING-WATER.  127 

charged  with  one-tenth  its  bulk  of  clean  borings  or  punch- 
ings,  filled  completely  with  water  and  shaken  for  four  min- 
utes, in  such  manner  that  the  iron  particles  are  continuously 
showered  through  the  liquid.  The  water  is  then  aerated 
by  agitating  it  in  a  large,  thoroughly  clean  glass-stoppered 
bottle.  With  some  (e.  g.,  peaty)  waters,  it  will  be  of 
advantage  to  allow  about  200  c.  c.  of  air  to  remain  in  the 
bottle  in  which  the  shaking  with  iron  is  performed,  occa- 
sionally removing  the  stopper  to  renew  the  air.  (Con- 
tinuous aeration  during  treatment  is  provided  for  in  the 
apparatus  used  on  the  large  scale.)  The  liquid  is  allowed 
to  stand  from  a  few  minutes  to  four  hours,  depending  on 
the  rapidity  with  which  the  iron  separates,  and  is  then 
filtered  through  the  sand  filter  (Fig.  n),  or  through  a  well- 
washed  cotton  plug  inserted  in  the  neck  of  a  funnel.  Sat- 
isfactory purification  as  regards  ammonium  compounds 
cannot  be  obtained,  but  with  proper  attention  to  cleanliness, 
the  figures  for  total  organic  nitrogen,  nitrogen  by  perman- 
ganate, and  oxygen-consuming  power  will  be  trustworthy. 

The  following  results  were  obtained  by  Dr.  Beam  and 
myself  in  the  treatment  of  Delaware  River  water  at  Lard- 
ner's  Point  pumping  station,  Philadelphia.  The  purifier 
was  capable  of  delivering  100,000  gallons  per  24  hours. 
All  figures  are  in  parts  per  million. 

September,  1890. 

Before  Treatment.     After  Treatment. 
Nitrogen  as  ammonium,  .04  .03 

"        as  permanganate,          .27  .09 

November,  1890. 

Nitrogen  as  ammonium,  .084  .034 

"         by  permanganate,          .091  .049 

"        as  nitrites,  traces.  none. 

The  apparatus  was  subsequently  transferred  to  Belmont 


128  INTERPRETATION    OF   RESULTS. 

pumping  station,  Philadelphia,  and  bacteriologic  examina- 
tions made.  The  applied  water  was  taken  from  Belmont 
reservoir  which  was  supplied  from  the  Schuylkill  River. 
The  cultivation  was  made  in  alkaline  meat-extract-peptone- 
gelatin  at  ordinary  temperatures.  The  figures  represent  the 
number  of  points  of  microbic  life  in  one  c.  c.  of  the 
sample. 

Date.  Applied  -water.                   Effluent  -water. 

Nov.  II,  innumerable  36 

"  13,  4,900  32 

"  30,  2,860  49 

Dec.  7,  22,100  79 

"  u,  17,100  560 

"  14,  16,000  60 

"  18,  14,500  27 

The  sample  for  December  1 1  was  taken  just  after  filter- 
cleaning.  Moreover,  the  weather  had  been  very  cold  and 
a  film  of  ice  formed  around  the  sides  of  the  tank  and  over 
the  bottom ;  the  expansion  of  this  ice  pushed  the  sand 
away  from  the  sides  of  the  tank.  A  thaw  occurred  and  a 
space  was  left  all  around  the  sand-bed  through  which  the 
water  passed  without  proper  filtering. 

Laboratory  experiment  on  a  sample  of  water  from  the 
Mississippi  River  at  Memphis,  Tenn. 

Before  Treatment.    After  Treatment. 

Oxygen  absorbed  at  212°  F.,        2.88  0.36 

In  the  laboratory  of  the  State  Board  of  Health  of  Massa- 
chusetts Dr.  Drown  investigated  the  effect  of  various 
methods  of  aeration,  such  as  exposing  water  in  bottles  to 
the  air  of  the  room,  drawing  a  current  of  air  through  by 
means  of  an  aspirator,  shaking  it  in  a  bottle  by  machin- 
ery, and  exposing  it  to  air  under  pressure  of  from '60  to 
75  pounds.  While  no  appreciable  benefit  as  far  as  re- 


PURIFICATION    OF    BOILER   WATERS.  129 

gards  the  organic  matter  and  its  decomposition-products 
occurs,  aeration  appears  to  prevent  the  growth  of  algae, 
with  the  troublesome  accompaniments  of  bad  tastes  and, 
odors.  It  may  also  have  a  beneficial  effect  upon  ground- 
waters  containing  considerable  amounts  of  iron.  These 
waters  are  often  clear  when  first  drawn,  but  become  turbid 
and  yellow  in  a  few  hours  by  the  separation  of  ferric- 
hydroxid  by  oxidation.  Waters  from  considerable  depth 
often  contain  so  little  free  oxygen  that  this  oxidation  does 
not  occur  until  they  reach  the  surface.  By  applying  an 
aeration  method  the  change  may  be  hastened,  and  by  some 
simple  process  of  rapid  filtration  afterward  applied,  the 
water  will  be  made  clear  and  remain  so. 

A  material,  designated  by  the  patentee  as  "  magnetic 
carbid  of  iron,"  has  been  used  for  the  purification  of  sew- 
age. It  is  made  by  heating  hematite  with  coke  and  saw- 
dust, so  as  to  reduce  the  ore  to  the  composition  of  mag- 
netic oxid. 

Purification  of  Boiler  Waters. — The  problems  pres- 
ent in  the  treatment  of  boiler  waters  are  usually  the 
removal  of  the  calcium  carbonate  and  sulphate,  and  magne- 
sium carbonate  and  chlorid.  Both  carbonates  are  appreci- 
ably soluble  in  pure  water.  About  one  grain  of  calcium 
carbonate  to  the  gallon  is  usually  stated  to  be  the  propor- 
tion dissolved,  but  it  has  been  pointed  out  by  Allen  that 
solutions  can  be  obtained  containing  twice  this  amount. 
If  the  water  contains  carbonic  acid  it  will  take  up  a  much 
greater  proportion  of  the  carbonates,  but  in  this  case  they 
will  be  deposited  from  the  solution  by  boiling.  This  has 
been  accounted  for  by  supposing  the  existence  of  soluble 
bicarbonates,  which  are  decomposed  by  the  boiling. 

.  T 


130  INTERPRETATION    OF    RESULTS. 

Nearly  all  of  these  carbonates  can  be  thrown  out  of  solution 
by  any  means  that  will  deprive  the  water  of  the  carbonic 
acid.  Sodium  hydroxid  is  often  employed  for  the  purpose, 
and  should  be  added  in  quantity  just  sufficient  to  form 
normal  sodium  carbonate.  If  there  are  present  in  the 
water  calcium  and  magnesium  chlorids  and  sulphates,  these 
also  will  be  decomposed  and  precipitated  by  the  sodium 
carbonate  so  formed.  If  the  amount  of  sodium  carbonate 
formed  is  not  sufficient  to  decompose  all  of  these  bodies, 
a  sufficient  quantity  should  be  added  with  the  sodium 
hydroxid  to  effect  the  complete  decomposition.  The  pre- 
cipitate is  allowed  to  settle  or  filtered  off. 

In  cases  in  which  the  feed- water  is  heated  before  it  enters 
the  boiler,  it  may  only  be  necessary  to  add  to  the  water 
sodium  carbonate  in  quantity  sufficient  to  decompose  the 
calcium  and  magnesium  chlorids  and  sulphates,  since  the 
heat  alone  will  suffice  to  throw  down  the  carbonates. 

Care  should  be  taken  in  these  precipitations  that  no  more 
sodium  hydroxid  is  added  than  is  required  for  the  precipi- 
tation, since  any  excess  would  tend  to  corrode  the  boiler. 

Clark:  s  process  consists  in  treating  the  water  with  calcium 
hydroxid  (lime-water).  This  precipitates  the  calcium  and 
magnesium  carbonates  by  depriving  the  water  of  its  free 
carbonic  acid.  It  has,  of  course,  no  effect  upon  the  cal- 
cium sulphate.  It  is  to  be  noted  that  the  proportion  of 
calcium  hydroxid  which  is  to  be  added  must  be  calculated 
from  the  amount  of  free  carbonic  acid  existing  in  the  water, 
and  not  from  the  amount  of  carbonates  to  be  removed. 
The  precipitate  will  usually  require  at  least  twelve  hours 
for  complete  subsidence,  but  after  three  or  four  hours  the 
water  will  be  sufficiently  clear  for  some  purposes.  If  a 
filter  press  is  used,  as  in  Porter's  process,  the  time  required 


PURI FICATION   OF    BOILER   WATERS.  131 

for  clarification  is  very  much  shortened.  Another  advan- 
tage of  this  process  is  the  use  of  a  solution  of  silver  nitrate, 
in  order  to  determine  more  conveniently  the  proportion  of 
calcium  hydroxid  which  is  to  be  employed.  The  lime  is 
first  slaked  and  dissolved  in  water,  and  the  water  to  be 
softened  run  in  and  thoroughly  mixed  with  it.  From  time 
to  time  small  portions  are  taken  out  and  a  few  drops  of  a 
solution  of  silver  nitrate  added.  As  long  as  the  lime  is  in 
excess  a  brownish  coloration  is  produced.  When  this  has 
become  quite  faint,  and  just  about  to  disappear,  the  addi- 
tion of  the  water  is  discontinued,  and,  after  a  short  time, 
the  water  is  filtered  by  means  of  the  press. 

Soluble  phosphates  added  to  a  water,  precipitate  com- 
pletely in  a  flocculent  condition  any  calcium,  magnesium, 
iron,  or  aluminum.  This  reaction  can  be  best  applied  by 
using  the  tri-sodium  phosphate  (Na3PO4  -f-  i2H2O),  which 
is  now  a  commercial  article.  By  reason  of  the  facility  with 
which  this  substance  loses  a  portion  of  its  sodium  to  acids, 
it  acts  not  only  as  a  precipitant  to  the  above  materials,  but 
will  neutralize  any  free  mineral  acid  present  in  the  water. 
From  evidence  submitted  by  those  who  have  used  the  pro- 
cess on  the  large  scale,  it  appears  that  not  only  is  no  hard 
scale  formed,  but  that  scale  already  existing  prior  to  its 
use  is  gradually  disintegrated  and  removed  with  the  sludge. 
Experiments  indicate  that  no  injury  results  from  an  excess 
of  the  material ;  but  the  economical  employment  of  the 
method,  especially  with  very  hard  waters,  can  only  be 
based  upon  a  correct  analysis,  and  an  estimation  of  the 
phosphate  required  for  the  precipitation.  In  many  cases 
the  composition  of  the  water  will  be  such  that  a  partial 
precipitation  will  be  sufficient. 


132  INTERPRETATION  OF  RESULTS. 

Of  late  years  considerable  success  has  been  obtained  by 
the  use  of  fluorids  as  precipitants  of  scale-forming  elements. 

Waters  rich  in  ferrous  compounds  may  be  purified  by 
thorough  aeration  and  filtration,  the  iron  being  separated 
as  ferric  hydroxid.  Simple  filtration  through  a  bed  of 
manganese  dioxid  will  accomplish  the  same  purpose. 

IDENTIFICATION  OF  THE  SOURCE  OF  WATER. 

The  determination  of  the  course  of  underground  streams, 
and  of  communications  between  collections  of  water,  is 
often  an  important  practical  problem.  In  geologic  and 
sanitary  surveys,  valuable  information  may  occasionally  be 
gained.  The  method  generally  pursued  when  connection 
between  water  at  accessible  points  is  to  be  detected,  is  to 
introduce  at  one  point  some  substance  not  naturally  exist- 
ing in  the  water,  and  capable  of  recognition  in  small 
amount.  Lithium  compounds  are  among  the  best  for  this 
purpose.  They  are  not  frequent  ingredients  of  natural 
waters,  and  are  easily  recognized  by  the  spectroscope. 
Lithium  chlorid  is  the  most  suitable.  The  quantity  to  be 
employed  will  vary  with  circumstances.  It  scarcely  needs 
to  be  stated  that  the  waters  under  examination  should  be 
carefully  tested  for  lithium  before  using  the  method. 

When  the  lithium  method  is  inadmissible,  recourse  must 
be  had  to  other  substances  of  distinct  character,  such  as 
strontium  chlorid,  but  this  possesses  the  disadvantage  that 
a  considerable  amount  may  be  rendered  insoluble,  and 
thus  lost  in  the  ordinary  transit  through  soil.  Recently,  use 
has  been  made  of  organic  coloring  matters  of  high  tinct- 
orial power,  one  of  the  most  suitable  of  which  is  fluores- 
cein,  C20Hi2O5,  a  derivative  of  benzene.  This  will  com- 
municate a  characteristic  and  intense  fluorescence  to  many 


IDENTIFICATION    OF   THE   SOURCE    OF   WATER.          133 

thousand  times  its  weight  of  water.  An  entire  river  may 
be  colored  by  a  few  kilograms.  By  its  use  an  under- 
ground communication  was  demonstrated  to  exist  between 
the  Danube  and  the  Ach,  a  small  river  which  flows  into 
the  Lake  of  Constance.  The  coloration  is  distinct  only 
in  alkaline  liquids.  Other  colors,  such  as  anilin-red, 
may  be  employed.  For  detecting  leakage  from  cesspools 
and  cisterns,  sanitary  inspectors  occasionally  employ  water 
colored  by  Prussian  blue. 

I  am  indebted  to  Dr.  F.  P.  Vandenburgh,  who  conducted 
the  investigation,  for  a  description  of  an  instance  of  the 
application  of  the  above  methods.  In  a  suit  at  law  grow- 
ing out  of  use  of  a  creek  for  the  supply  of  Syracuse, 
N.  Y.,  it  was  alleged  that  the  creek  supplied  a  spring 
which  was  used  by  a  manufacturing  establishment.  Tests 
of  the  water  of  creek  and  spring  for  lithium  were  made, 
ten  gallons  of  each  being  evaporated,  with  negative 
results.  Twenty-five  pounds  of  lithium  carbonate  were 
converted  into  chlorid  and  poured  into  the  stream  about 
half  a  mile  from  the  spring.  Samples  of  ten  gallons  each 
were  taken  out  of  the  spring  by  almost  continual  dipping 
during  forty-eight  hours  following.  Twenty  of  these 
samples  were  examined  and  lithium  found  in  each. 

Ten  pounds  of  fluoresce'in  were  introduced  at  a  point 
about  one  mile  above  the  spring  and  the  characteristic 
fluorescence  appeared  at  the  spring  about  six  hours  after 
its  introduction  into  the  creek.  The  greatest  intensity  of 
color  was  between  six  and  ten  hours  after  its  introduction. 

A  more  important  feature  of  the  problem  in  a  sanitary 
point  of  view  is  the  determination  of  the  source  of  a 
given  current  or  collection  of  water,  when  such  source  is 
inaccessible.  Problems  of  this  character  are  not  infre- 
quent in  large  cities  in  which  the  systems  of  water  supply 


134  INTERPRETATION   OF   RESULTS. 

and  drainage  are  defective,  thus  giving  occasion  to 
accumulations  of  water  in  cellars  and  similar  places. 
Often,  in  these  cases,  no  extended  explorations  can  be 
made,  by  reason  of  the  adjacent  buildings  and  conflicting 
property  interests,  and  the  question  may  arise  whether  the 
water  proceeds  from  a  leaky  hydrant,  drain,  sewer,  or  sub- 
soil current.  It  is  obvious  that  in  the  case  of  the  collection 
of  water  in  a  cellar  from  causes  other  than  surface  wash- 
ings or  entrance  of  rain,  it  must  have  passed  through  some 
distance  of  soil,  and  in  built-up  districts  will  almost  cer- 
tainly be  charged  with  organic  refuse.  To  correctly 
interpret  the  results,  it  will  be  necessary  to  know  the 
general  character  of  the  subsoil  water  of  the  district  and 
the  composition  of  the  public  supply.  As  a  rule,  the 
transmission  of  water  through  moderate  distances  of  soil 
will  not  materially  increase  the  mineral  constituents. 
Hence,  if  the  sample  contains  an  excess  of  dissolved  mat- 
ters as  compared  with  the  water  supply  of  the  district,  it 
may  reasonably  be  inferred  that  it  is  derived  from  a  drain, 
sewer,  or  subsoil  current. 

In  these  investigations  it  will  generally  be  sufficient  to 
determine  the  total  solids,  odor  on  heating,  chlorin, 
nitrates  and  nitrites.  The  following  figures  are  from  some 
results  obtained  in  investigations  made  in  association  with 
Mr.  Chas.  F.  Kennedy,  Chief  Inspector  to  the  Board  of 
Health  of  this  city  : — 

CELLAR  WATER. 


City  Supply.  No.  i.  No.  2.  No.  3. 

Total  solids, 115  140           66 1  640 

Odor  on  heating,  .    .    .  faint  faint  strong  urinous 

Chlorin,      4  6.4           77.0  128.0 

N  as  nitrates,    ....      0.7  l.o              3.5  none 

"  "  nitrites,      ....  none  present  present  none 


IDENTIFICATION    OF   THE   SOURCE    OF   WATER.          135 

Sample  No.  i  was  taken  from  a  cellar  in  which  a  small 
amount  of  water  had  been  almost  constantly  present  for  a 
long  time,  and  of  which  the  source  could  not  be  ascertained. 
The  results  of  analysis  led  to  the  view  that  since  it  resem- 
bled in  composition  the  city  supply,  it  was  derived  from 
a  leaky  hydrant  pipe.  The  parties  in  interest  were  not  in- 
clined to  accept  this  opinion,  but  the  examination  of  the 
condition  of  the  hydrant  on  an  adjacent  property  showed 
a  leak,  which  being  repaired  the  water  ceased  to  appear  in 
the  cellar.  In  this  case  it  was  found  that  the  water  had 
passed  through  twenty-two  feet  of  earth.  In  the  second 
case  the  sample  is  seen  to  be  very  impure,  and  it  was  sug- 
gested that  it  was  derived  directly  from  a  leaky  drain, 
which  upon  exploration  proved  to  be  the  case.  In  the 
third  sample,  the  high  chlorin,  strong  urinous  odor  and 
absence  of  nitrates  and  nitrites,  pointed  unmistakably  to 
recent  and  profuse  contamination  with  sewer  water. 

Occasionally  the  analytic  results  will  be  ambiguous,  and 
it  is  advisable  to  make  examinations  of  more  than  one 
sample,  since  accidental  circumstances,  rain-fall,  etc.,  may 
affect  the  composition  of  the  water. 

Instances  of  the  contamination  of  water  by  unusual  sub- 
stances are  occasionally  noted,  and  these  sometimes  afford 
a  clue  to  the  source  of  the  water.  '  Among  the  instances 
of  this  kind  within  my  own  experience  may  be  noted  the 
contamination  with  petroleum  and  with  soap.  In  the 
former  case  it  was  evident  that  the  contamination  was  from 
a  leaky  pipe  connecting  two  refineries.  In  the  latter  it 
was  shown  to  be  derived  from  an  adjoining  building  used 
as  a  laundry. 


ADDENDA. 


To  page  63. 

Extended  observations,  especially  in  Massachusetts, 
have  shown  that  reservoirs  intended  for  even  moderately 
prolonged  storage  of  water  should  be  clean,  that  is,  or- 
ganic matter  of  any  kind  should  not  be  allowed  to  accu- 
mulate on  the  bottom  and  sides.  Dr.  Drown  states  (Rep. 
S.  B.  of  H.  of  Mass. ,  1891)  that  while  the  water  in  one 
basin  became  foul  from  stagnation,  in  another  which  was 
carefully  prepared  by  the  removal  of  all  soil  and  vegetable 
matter,  and  is  supplied  by  a  brown,  swampy  water  from  a 
district  almost  entirely  free  from  pollution,  the  water  is 
good  at  a  depth  of  forty  feet. 

In  Philadelphia,  where  large  storage  reservoirs  are  used 
for  water  that  is  often  very  muddy,  but  little  trouble  from 
the  growth  of  microscopic  organisms  occurs.  These  reser- 
voirs are  artificial  basins. 

To  page  64. 

Owing  to  the  great  differences  in  the  size  of  micro- 
scopic organisms,  the  mere  enumeration  of  their  numbers 
is  not  always  an  index  of  the  amount  of  living  matter  in 
suspension.  To  obviate  this,  Mr.  Geo.  C.  Whipple,  biolo- 
gist to  the  Boston  Water  Board,  has  suggested  a  standard 
unit  of  size,  estimating  by  means  of  it  the  total  volume  of 
the  organisms,  and  not  their  number.  He  finds  by  this 
method  that  the  analytic  and  biologic  results  correspond 
much  more  closely  than  when  mere  numbers  are  recorded. 
The  unit  is  an  area  of  400  microns,  that  is,  a  square  of  20 
136 


ADDENDA.  137 

microns  on  a  side.  The  results  are  stated  in  number  of 
standard  units  per  c.  c.  A  detailed  account  of  the  method 
and  of  some  results  obtained  by  it  will  be  found  in  The 
Amer.  Month.  Mic.  Jour.,  1894,  p.  337. 

Mr.  Whipple  has  investigated  the  conditions  influencing 
the  growth  of  the  microscopic  organisms  in  water.  He  finds 
that  diatoms  thrive  best  with  a  supply  of  nitrates  and  a 
free  circulation  of  air ;  temperature  alone  has  no  very 
direct  effect.  Infusoria  will  be  found  in  largest  numbers 
when  the  water  contains  the  greatest  amount  of  finely 
divided  organic  matter.  When  the  conditions  bring  about 
a  circulation  of  the  water,  the  organisms  are  not  only 
brought  constantly  in  contact  with  new  food  materials,  but 
are  enabled  to  reach  the  upper  layers  of  the  water  where 
oxygen  is  abundant. 

To  page  63. 

In  a  private  communication  of  recent  date,  from  Mr. 
George  W.  Fuller,  of  the  Experiment  Station  at  Lawrence, 
•  Massachusetts,  I  am  furnished  with  the  following  informa- 
tion of  great  practical  value  in  the  bacteriologic  examina- 
tion of  drinking  water.  At  this  station  the  methods  for 
the  isolation  of  the  so-called  typhoid  bacillus  are  those 
described  in  the  "  Report  of  the  Massachusetts  State  Board 
of  Health  "  for  1891,  page  637.  The  only  additional  step 
is  to  employ  Wurtz'  litmus-lactose-agar.  This  consists  of 
nutrient  agar-agar  of  definite  reaction.  See  below  for 
the  methods  for  determining  reaction,  to  which  2  to  3  per 
cent,  of  lactose  is  added.  It  is  sterilized  and  then  enough 
sterilized  litmus  solution  added  to  give  a  decided  blue  tint. 
The  bacilli  included  under  the  designation  B.  typhus  abdom- 
inalis  do  not  produce-  fermentation  with  this  medium,  but 


138  ADDENDA. 

some  common  water-bacteria  do.  (Abbott,  "Manual  of 
Bacteriology.")  This  is  found  to  be  of  much  assistance. 

The  methods  are  employed  with  reasonable  confidence 
at  Lawrence,  where  the  observers  are  fairly  familiar  with 
the  bacterial  flora  of  the  water  examined.  Concerning 
waters  from  elsewhere  much  significance  is  attached  to  the 
presence  or  absence  of  the  B.  coli  communis. 

Mr.  Fuller  has  also  favored  me  with  a  comprehensive  ab- 
stract of  a  valuable  communication  presented  by  him  to  the 
Convention  of  Bacteriologists,  to  which  reference  is  made 
on  page  103.  After  discussing  the  influence  of  reaction 
upon  the  various  phenomena  taking  place  in  culture-media, 
it  was  pointed  out  that  all  regular  culture-media  as  used 
are,  strictly,  neither  neutral,  acid,  or  alkaline,  but  the 
reaction  depends  upon  the  indicator  used.  Many  are 
alkaline  to  litmus  and  acid  to  phenolphthalein  ;  the  cause  of 
this  is  twofold, — the  presence  of  acid  phosphates  and  of 
proteids ;  the  latter  are  amphoteric,  but  the  acid  reaction 
predominates.  Phenolphthalein  is  the  best  and  most  deli- 
cate agent  for  determining  reaction  in  culture-media. 
Under  ordinary  circumstances  the  phosphate  present  is 
Na2HPO4.  To  all  other  indicators,  except  turmeric  and 
phenolphthalein,  this  salt  is  alkaline,  to  the  latter  it  is  neu- 
tral. Experiments  have  shown  that  this  phosphate  exerts 
little  influence  upon  bacterial  development ;  in  fact,  it  is 
less  active  than  sodium  chlorid.  Hence,  with  litmus  as  an 
indicator,  this  compound  reacts  alkaline  and  prevents  a 
proper  addition  of  alkali,  and  as  the  amounts  of  phosphates 
vary  in  different  lots  of  culture-media,  the  degree  of  reac- 
tion cannot  be  accurately  controlled  by  means  of  litmus. 

Mr.  Fuller  recommends  "neutrality  to  phenolphtha- 
lein "as  a  "datum  point"  for  reaction.  The  expression 


ADDENDA.  139 

of  the  reaction  in  parts  or  in  percentage  is  inaccurate  and 
awkward.  It  is  suggested  that  all  reaction  be  expressed  in 
terms  of  normal  solution  necessary  to  render  one  liter  of  the 
medium  neutral  to  phenolphthalein.  As,  ordinarily,  the 
media  are  acid,  it  is  convenient  to  call  the  acid  number 
plus,  alkaline  minus. 

The  procedure  at  Lawrence  is  to  get  all  ingredients  in 
solution,  mix  well,  place  5  c.  c.  in  a  15  cm.  porcelain 
dish,  add  45  c.  c.  of  distilled  water,  boil  three  minutes, 
titrate  with  ~  alkali,  using  phenolphthalein  as  an  indicator, 
calculate  the  amount  of  normal  alkali  necessary  to  make 
the  main  bulk  of  the  solution  neutral,  heat  for  the  usual 
period,  filter,  and  titrate  again.  The  solution  is  now  rather 
acid,  and  hydrochloric  acid  is  added  in  such  amount  that 
to  make  one  liter  of  the  medium  neutral  to  phenolphthalein 
15  c.  c.  of  normal  alkali  is  necessary.  This  is  for  special 
work.  In  general  work,  using  i  c.  c.  of  the  water-sample 
to  5  c.  c.  of  culture-medium,  the  acidity  is  increased  one- 
fifth  to  offset  the  dilution. 

The  following  table,  condensed  from  Mr.  Fuller's  com- 
munication, shows  very  clearly  how  reaction  influences  the 
number  of  points  of  microbic  life  developed  in  any  given 
sample,  and  confirms  the  observations  on  page  102. 


c.  c.  OF  NORMAL  SOLU- 
TION   REQUIRED    TO 

POINTS  OF 

MICROBIC  LIFE  IN  ONE  c.  c. 

NEUTRALIZE        ONE 
LITER  OF  THE  CUL- 
TURE-MEDIUM. 

Laivrence  Seivage. 

Merrimack  River 
Water. 

Filtered  Water. 

40 

168,000 

IOO 

4 

25 

1,720,000 

7,800 

84 

2O 

2,688,000 

15,000 

I84 

5 

2,625,000 

6,900 

80 

o 

2,234,000 

5,800 

66 

—  IO 

2,230,000 

3,200 

48 

—  25 

1,520,000 

20O 

J3 

—  indicates  alkalinity  to  phenolphthale 


140  ADDENDA. 

As  an  illustration  of  the  difficulty  of  recognizing  a 
specific  typhoid  germ  I  may  mention  that,  although  there 
is  every  reason  to  believe  that  the  Schuylkill  water  supplied 
to  Philadelphia  causes  considerable  typhoid  fever,  Dr.  A. 
C.  Abbott,  of  the  Department  of  Hygiene  of  the  Uni- 
versity of  Pennsylvania,  informs  me  that  he  has  never 
been  able  to  find  in  that  water  the  typical  bacillus. 


ANALYTIC    DATA. 

FACTORS  FOR  CALCULATION. 

Parts  per       100,000  X  -7  =  Grains  per  Imperial  Gallon 

"       "      1,000,000  >(  -°7  =       "        "          "  " 

"       "        100,000  X  .583  =       "        "       U.  S. 

"      "     1,000,000  x  -058  =     "       "        "  " 

"       "      1,000,000  X  -00833  =  Pounds  per  1000  U.  S.  Gal. 

Grains "     Imp.  gallon  -=-  .7  =  Parts  per      100,000 

"       "       "         "  -4-  .07  =      "       "      1,000,000 

"      "     U.  S.    "  ~  .583  =     "      "        100,000 

"      "       "        "  -=-  .058  =     "      "     1,000,000 

Parts  per  100,000  divided  by  2  and  quotient  increased  one-tenth  gives 
approximately  grains  per  U.  S.  Gallon. 


A1203  

...     x    -529 

=  Al 

AgCl,    ..... 

....  X     -247 

=  Cl 

BaSO4,     .... 

....  X    -588 

=  Ba 

BaSO4  

....  X    -412 

=  S04 

B203  

....  X     -3'4 

=  B 

CaO  

....  x  -714 

=  Ca 

CaC03,     .... 

....  X    -40 

=  Ca 

Cl,    

....  X  i-65 

=  NaCl 

FeA.  

....  X    -7 

KC1  

....  X    -524 

=  K 

2KC1,  PtCl4,    .    . 

....  X     -16 

=  K 

2KC1,  PtCl4,    .    . 

.  .  .  -x  .30 

=  KCI 

Mg,PA,      •    •    • 

....  X    -218 

=  Mg 

Mg2P207,     .    .    . 

....  x  .853 

=  PO4 

MnS,    

.   .   .   .  X    -632 

=  Mn 

NaCl,   ..... 

•  •  •  -X    -393 

=  Na 

N,     

X  4-43 

=  NO, 

N,     

....  X  3-28 

=  N02 

N,     

....  x  5-85 

=  Ca(N08), 

NH3,    

...  X    -823 

=  N 

141 

142 


CONVERSION    TABLE. 


CONVERSION  TABLE. 


PARTS 

PER 

MILLION 

U.  S   GALLON. 

PER 

IMP.  GAL. 

PER 

MILLION. 

U.  S.  GALLON. 

IMP.  GAL. 

I 

.058 

.07 

26 

.508 

1.82 

2 

.116 

.14 

27 

.566 

1.89 

3 

.174 

.21 

28 

.624 

I.96 

4 

.232 

.28 

29 

682 

2.03 

5 

.290 

•35 

30 

.740 

2.10 

6 

.348 

.42 

31 

.798 

2.17 

7 

.406 

•49 

32 

•  856 

2.24 

8 

.464 

•56 

33 

.914 

2.3I 

9 

•522 

•63 

34 

.972 

2.38 

10 

.580 

.70 

35 

2.030 

2.45 

ii 

.638 

•77 

36 

2.088 

2.52 

12 

.696 

.84 

37 

2.146 

2-59 

13 

•754 

.91 

38 

2.204 

2.66 

H 

.812 

•98 

39 

2.262 

2-73 

15 

.870 

1.05 

40 

2.320 

2.80 

16 

.928 

1.  12 

4i 

2.378 

2.87 

17 

.986 

I.I9 

42 

2.436 

2.94 

18 

1.044 

1.26 

43 

2.494 

3.01 

19 

.102 

i-33 

44 

2.552 

3.08 

20 

.160 

1.40 

45 

2.610 

3-i5 

21 

.218 

i-47 

46 

2.668 

3-22 

22 
23 

.276 
334 

1-54 
1.61 

47 
48 

2.726 
2.784 

329 
3.36 

24 

•392 

1.68 

49 

2.842 

3-43 

25 

1.450 

1-75 

50 

2.900 

3-50 

TABLE   OF   DISSOLVED    OXYGEN. 


DIBDIN'S  TABLE  OF  OXYGEN  DISSOLVED  BY  WATER  AT  VARIOUS 

TEMPERATURES,  EXTENDED  TO  GIVE  THE  WEIGHT  OF  OXYGEN 

PER  LITER.     CORRECTED  TO  o°  C.  AND  76omm-  PRESSURE. 


Temperature 
Fahrenheit. 

41°   .    . 

42      .     . 

Temperatu, 
Centigrade 
....      5-00°  . 

•    -   -   -    5-55    - 

Cubic  Inches  of 
"e      Oxygen  per  Gallon 
(70000  Grains). 
....  2.IOI   .     .     . 
....  2.074  .     .     . 
2  048 

Milligrams 
of  Oxygen 
per  Liter. 

.    .     .  10.84 
.     .  10.72 

44     •    • 

....    6.66 

2  O22 

10  45 

45     •    • 
46     .    . 

....    7.22    . 
•    •   •   •    7-77 

...   1.997        •     • 

I      Q7-J 

.    .    .  10.30 
10  18 

47     •   • 

•    8-33 

48     .    . 
49 

....    8.89    . 

....   1.927   .     .     . 

i  oot; 

•    •    •    9-94 

Q  8^ 

50     .    . 
5i     •    • 

52 

....   IO.OO     . 

.  .  -  .  10.55  . 

II  1  1 

.       .   .  1.884  •   •   • 
....  1.864  •   • 
i  844. 

.     .     .     9.72 
.     .     .      9.6l 

53     •    • 
54     •    • 
55     •    • 
56     .    . 
57     •    • 

....  11.66    . 

....   12.22     . 
....   12.77     - 
....   13-33     • 
....   13  89     . 

....  1.826  .   .   . 
....  1.808  .    .    . 
....  1.791  .    .    . 
....  1-775  -    •    • 
.    .    .    .  1.760  .    .    . 

.     .     .      9.42 

•    •    •    9-33 
.    .    .    9.24 

•    •    •    9-15 
.    qo8 

58     -    - 
59     •    • 

....   1444     • 
.     .     .     .   I5.OO     . 

....  1.746  .    .    . 
.    .    .    .  1.732  .   . 

.    .    .     9.01 
8.94 

60     .    . 
61     .    . 
62     .    . 
63     •    • 
64     .    . 
65     .    . 
66     .    . 

....   15-55     • 

.    .    .    .  1  6.  1  1    . 
....  16.66    . 
....  17.22    . 
-    •  17-77    • 
....  18.33    • 
.  18  89    . 

...  1.719  .    .    . 
....  1.706  .   .    . 
....  1.695  .    .    . 
....  1.683  •    •    • 
....  1.674  .    .    . 
....  1.667  .    .    . 
i  660  . 

.    .    .     8.87 
.    .    .     8.80 
.    .    .    8.74 
.    .    .    8.68 
.    .    .    8.64 
.    .    .    8.60 
8  q6 

67     .    . 
68     .    . 
69     .    . 
70     .    . 

The  table  is  ( 
corrections  for 
limits  of  experi 

....  19  44    . 
....  20.00    . 
....  20.55    • 

....  21.  II      . 

:alculated  for  a  barom 
variations  from  this, 
mental  error. 

....  1.652  .    .    . 
....  1.644  •    •    - 
....  1.639  .    .    . 
....  1.634  .   .    . 

etric  pressure  of  760  mm., 
but  such   corrections  are 

.    .    .    8.52 
.    .    .    848 
.    -    .    8.45 
•    •    •    8.43 

and  would  require 
mostly  within  the 

144 


ANALYSIS   OF   RAIN   AND   SUBSOIL   WATERS. 


ANALYSES  OF  RAIN  AND  SUBSOIL  WATERS. 
Milligrams  per  Liter. 


. 

O 

1 

1 

a 

O          0° 

From. 

C/3 

.s 

^ 

2 

a 

£ 

"rt 

i 

£ 

3 

B 

a 

H 

a 

z 

fc 

* 

fc 

Rain  water. 

Bellefonte—  collected  by 
Prof.     Wm.    Frear,    after 

5 

none 

0.148 

0.280 

none 

none 

Subsoil  water. 

long  rain. 
Wynnewood—  pool    fed 
by  underground  spring. 
Wynnewood  —  well  about 
150  yards  from  above. 

65 
60 

6.20 

4.00 

0.032 

0.024 

0.024 

none 
none 

2-3 

3-5 

„ 

Wynnewood  —  well    pol- 
luted by  farm-yard  drain- 
age ;  about  500  yards  from 

i6.oo|  0.208 

0.028 

none 

14.2 

pool. 

« 

Pump  -well    in   densely, 
populated  district.  Highly;   1120 

J.~ 

3.120 

0  01 

33-° 

contaminated. 

« 

Newly  dug  well  in  popu- 
lated district.  Highly  con- 

620 

I20.00l   0.08 

2.00 

0.03 

1  6.0 

taminated. 

" 

Well  at  Barren  Hill,  130 
feet  deep.                                   «7° 

120.00  undet. 

undet. 

traces 

22  0 

RESULTS    FROM    SCHUYLKILL    RIVER. 


'45 


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146 


ANALYSES   OF   ARTESIAN   WATERS. 


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EXAMPLES   OF   CITY   SUPPLIES. 


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M 

If  1 

1 

I 

' 

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d 

it- 

i   ? 

1 

C/3 

I 

1 

8. 

1 

I 

0 

d 

ill 

S    c  *o 

• 

|  2   S 

s< 

s 

o 

§M 

m 

13  8 

1 

CO 

d 

1*3 

tf 

s 

8 

X 

u 

Surface. 

0 

? 

J 

H 

c 

8 

o" 

1" 

||-2 

1  g 

P 

1 

CO 

c         s 

i! 

| 

w 

1 

| 

0 

° 

f 

111 

^     i 

i|| 

o    |, 

o 

"4 

? 

°. 

d 

d 

j 

1 

" 

^  "o  JS 

t-4      J^ 

i 

a 

C3      D    P—  ' 

(Li 

M 

•0 

A 

1 

1 

8 

vo 

d 

1  1  jj. 

X 

* 

rll 

w 

Z 

M 

1 

0 

q 

1 

8 

s- 

|r|. 

§ 

J 

V? 

A 

0 

d 

0  Ji    "  -2 

S    cu  j£    S 

w 

^   s    >    cu 

j> 

h 

8 

1 

q 
K 

1 

0 

1 

f 

1 

g  *  o  i 

lili 

rt 

3 

; 

Z    • 

a  : 

a  ' 

4- 
If 

i    • 

li- 

«   g  "a  S 
JJ    §    <*    « 

| 

Class  of 

5 

1 

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c" 

jj 

}l 

l! 

& 

ft 

z 

*iil 

148  ANALYTIC   DATA. 


CULTURE-PHENOMENA  OF  SOME  IMPORTANT 

MICROBES. 

These  data  have  been  compiled  principally  from  the 
writings  of  the  Franklands  {Microorganisms  in  Water), 
Vaughan  (Bad.  of  Drink.  Water,  Proc.  Amer.  Ass'n 
Physicians,  1892),  and  Mace  (7K  Prat.  d.  Bad.}.  The 
references  are  indicated  by  appropriate  initials. 

In  the  first  column  -f-  means  "  liquefies,"  O  means  "  does  not  liquefy." 
"       second    "      -j-       "      "  aerobic,"    —     "      "  anaerobic." 

Jnd    1"       +       "      "grows>"      -     "      "grows  feebly." 
fourth]          °        "      "does  not  grow." 

The  species  marked  *  were  described  by  Jordan  {Rep. 
S.  B.  of  H.,  Mass.,  1890),  having  been  obtained  from  the 
sewage  of  Lawrence.  For  an  account  of  recent  study  of 
microbes  in  Ohio-River  water,  see  a  paper  by  John  W. 
Hill  (Trans.  Amer.  Soc.  Civ.  Eng.,  May,  1895). 

Under  the  term  B.  Aquatilis  sulcatus,  Weichselbaum  has 
described  five  varieties  designated  by  the  numbers  I  to  V. 
All  but  V  grow  somewhat  at  blood  heat. 


CULTURE-PHENOMENA. 


149 


ACTION  o> 
GELATIN. 

RELATION 
TO  OXYGBK 

ACTION  01 
PARIKTTI'S 
SOLUTION 

GROWTH  A- 
BLOOD-HEA' 

Bacillus 

albus,  V.,  

O 

+ 

O 

O 

** 

"      anaerobus,  V.,    

O 



-}_ 

-f- 

** 

"      putridus,  V.,   

_!_ 

_(_ 

O 

o 

<f 

aquatilis  sulcatus,  F.,  

0 

_|_ 

O 



M 

candicans,*F.,  

0 

_|_ 

_L 

chlorinus,  M  

4- 

-1_ 

ft 

coli-communis,  F.  ,  

o 

•f 

_l_ 

J. 

(t 

cinnabareus,  V.,    

O 

tt 

circulans,  F.,  

_1_ 

•4* 

*< 

cloaca;,*  F.,    

_l_ 

_f_ 

-j- 

U 

delicatulus,*  F.,     

+ 

_j_ 

_f- 

•'< 

erythrosporus,  F.,         
figurans,  V.,    
flavus,  M  

o 

-t- 

o 

- 

• 

fluorescens  liquefaciens,  V.,       .... 
"           non-liquefaciens.  V  
gasoformans,  V.,    
gracilis  aerobiens,  V.,      
"       anaerobiescens.V  ..... 

o 

0 

o 

! 

+  CCOO 

I  COOO 

•< 

helvolus.V.,    

+ 

+        o 

— 

* 

hyalinus,  F  ,*      

+          + 

+ 

' 

invisibilis,  V.,     

o     I    —         + 

-\- 

\ 

lactis  aerogenes,  F.,      
liquefaciens  albus,  V.,         

o     !     + 

o 

0 

o 
o 

\\ 

prodigiosus    M.,    

+         + 

o 

0 

reticularis,*  F.,  

'', 

rubescens,*  F.,  
rubidus,  V  

0 

1 

0 

o 

* 

subflavus,  V.,     

o 

~h 

0 

0 

subtilis,  M.,     

~h 

-j- 

superficial,  F.,     

-1-        + 

4~ 

tholeideum,  F.,  

0             + 

< 

typhi  abdominalis,  F.,     

0             + 

-j- 

ubiquitus,*  F.,    

0             -r 

* 

venenosus,  V.,    

O            —            + 

brevis.V.,     

O 

—       1       4" 

invisibilis.  V.,       

0             + 

\\ 

liquefaciens,  
violaceus,     

+        •+         o 

0 

Microcc 

ecus  aquatilis,  F.,  V.  
albus,  V  

o         +         + 

O      i      +            O 

± 

invisibilis,  V.,     .    .    .   . 

o         + 

o 

— 

"          magnus,    
(diplococcus)  aquatilis,  V.,    .   .    . 
(streptococcus)      " 
candicans,  V.,    

o     !     + 

0             + 
0             + 

0             + 

0 

o 
o 

0 

(0 

o 
o 

F  

o 

+ 

o 

o 

luteus'v  ' 

0             + 

o 

o 

«.KAo«M    V 

0             + 

0 

— 

Spirillum  cholerae  

+ 

" 

Finkleri,  M.,    

+ 

T 

+ 

INDEX. 


A  CIDS,  action  on  lead,  108 
**     Actinic  method  for  organic  matter, 
5° 

Bicarbonates  in  water,  129 
Biologic  examinations,  6t 
Black's  Island  well,  93,  146 

Action  of  water  on  lead,  107 

Blarez'  oxygen  process,  51 

Aeration  of  water,  128 

Boiler  mud,  in 

Agar-agar,  66 
Albuminoid  ammonia,  35,  96 

water,  109 
water,  points   to  be  determined 

Alkali  carbonates,  determination  of,  82 

in,  112 

Alkaline  permanganate,  33 
Allen,  on  boiler  waters,  in 

,  purification  of,  129 
,  statement  of  results  from, 

,  lead  in  water,  108 

112 

,  sulphuric  acid  in  water,  in 

Boric  acid  estimation,  85 

,  test  for  zinc,  56 

Bottle  culture,  69 

Alum,  action  of,  123 

for  test  solution,  33 

,  test  for,  58 

Burner,  low  temperature,  26 

,  use  of,  102 

Aluminum,  determination  of,  58,  75 

,  test  for,  58 

CALCIUM  bicarbonate,  129 

,  in  scale,  112 

carbonate,  action   in  boiler 

Amido-naphthalene,  44 

Ammonia,  albuminoid,  35,  96 

—  —  .solubility  of,  112 

,  free,  34 

compounds,  removal  of,  130 

,  free  water,  31 

,  determination  of,  76 

,  from  rain  water,  95 

—  —  ^  hydroxid  for  purifying  water,  131 

,  process,  2q 
Ammonium  chlorid,  standard,  31 

sulphate,  insolubility  of,  112 
sulphate,  action  in  boiler  water, 

molybdate,  51 

picrate  solution,  42 

Carbonates,  action  on  lead,  109 

Analysis,  statement  of,  89 

,  determination  of  normal,  82 

Analytic  operations,  21 

Carbon  filters,  115 

Anderson  and  Ogsten,  purification  of 

Carbonic  acid,  action  of,  18 

water,  124 

,  free,  determination  of,  84 

Antwerp  water,  purification  of,  126 

,  effect  on  microbes,  71 

Caustic  soda,  use   of,  in  boiler  water, 

waters,  composition  of,  146 
Arsenum,  detection  of,  56 

Cellar  waters,  examination  of,  134 
Chlorin,  determination  of,  28 

,  significance  of,  93 

BACHMAN'S  method,  36 

Chromium,  detection  of,  55 

Bacilli   species  of,  149 
Bacillus  typhosus,  culture  of,  72 

City  supplies,  147 
Clarifying  water,  23,  114 

Bacteriologic  examination,  61 

Clark's  process  for  purifying  water,  130 

Barium,  detection  and  estimation  of,  55 

Collection  of  samples,  20 

Barren  Hill  well,  20,  144 

Color  comparator,  38 

Barus,     Carl,     suspended     matters    in 

,  determination  of,  23 

water,  15 

,  significance  of,  91 

Basin,  platinum,  26 

Comparison  cylinders,  38 

151 


152  INDEX. 


Control  determination,  27,  77 
Conversion  of  ratios,  142 
Cooper,  A.  J.,  delicacy  of  tests,  61 
Copper,  detection  of,  60 

sulphate,  standard,  60 

zinc  couple,  43 

Corrosion  of  boilers,  no 
Cultivation  of  microbes,  67 
Culture-media,  67 
phenomena,  149 


T-\EEP  water,  18,  93,  146 

•*•'     Demijohn  for  water  samples,  21 

Denitrification,  18 

Dibdin,  table  of  dissolved  oxygen,  143 

Distilled  water,  whplesomeness  of,  92 

Driffield,   composition   of   boiler   mud, 

Drown,  aeration,  128 

Drown  and  Hazen,  ignition  of  residue, 

Drown  and  Martin,  nitrogen  determina- 
tion, 35 
Dupre,  dissolved  oxygen,  54,  100 


FERROUS   ammonium    sulphate, 
standard,  52 

Ferric  sulphate,  standard,  57 
Filter  paper,  23 
Filters,  Bischoff's,  116 

,  Pasteur-Chamberlain,  116 

,  sand,  118 

,  spongy  iron,  116 

Filtration,  115 
Fleck's  silver  method,  50 
Fluorescei'n,  use  of,  132 
Frankland,   purification     by   precipita- 
tion, 122 

and  Tidy,  standards  of  purity,  99 

,  isolation  of  microbes,  73 

,  nitrifying  bacillus,  17 

Fuller,  G.  W.,  culture-media,  137 
sand  filtration,  no 


GALLON,  Imperial,  89 
,'U.  S.,89*    9 

Gelatin  culture-media,  67 

,  liquefaction  of,  70 

Gerardin,  dissolved  oxygen,  10 

Gill's  method,  41 

,  method  for  lithium,  80 


•LJARDNESS,  determination  of,  81 

•*••*' ,  permanent,  81 

,  temporary,  81 

Hard  scale,  112 

water,  softening  of,  130 


Hehner's   cylinders   for  color  compari- 
son. 38 

,  method  for  hardness,  82 

History  of  water,  13 

Hunt,  T.  Sterry,  water  in  rocks,  16 

Hydrogen  sulphid,  titration  of,  81 

IDENTIFICATION     of    source     of 

•*•     water,  132 

Imperial  gallon,  89 

Interpretation  of  results,  89 

Indol  reaction,  71 

lodin,  centinormal,  81 

Iron,  action  of,  in  purification,  124 

compounds,  solution  by  water,  19 

,  determination  of,  57,  75 

,  significance  of,  93 

TT'JELDAHL  method,  38 
•*»•     Koch's  culture  method,  64 


T    ACM  OID,  use  of,  25 

•*-^     Lead,  action  of  water  on,  107 

Lead,  determination  of,  59 

,  nitrate,  standard,  60 

Leeds,  actinic  method,  50 

,  dissolved  oxygen,  100 

Lime,  purification  of  water  by,  114, 
Lithium  compounds,  use  of,  132 
,  detection  of,  86 

Litmus,  use  of,  25 
Locust  Point  well,  20,  146 


M 

Magnesium  chlorid, 
effects  of, 


AGNESI A  in  boiler  sludge,  in 
Magnesium,  determination  of,  75 


positions  ; 
compounds,  removal  of, 


Magnetic  carbid,  129 
Mallet,  ammonia  process,  96 
Manganese,  detection  of,  58 

Microbes,  table  of,  149 
Mine  water,  no 


NAPHTHYLAMINE,  44 
Nesslerizing,  34 
Nessler  reagent,  32 
Nitric  acid,  diluted,  57 
Nitrification,  17 
Nitrates,  action  in  boilers,  1 1 1 

,  determination  of,  41 

,  formation  of,  17 

,  significance  of,  98 

Nitrites,  determination  of,  44 
,  formation  of,  1 7 


INDEX. 


'53 


Nitrites,  significance  of,  98 
Nitrogen  in  ammonium  compounds,  29, 
94 

as  nitrites,  44 

as  nitrates,  41 

by  permanganate,  96 

,  oxidation  of,  16 
,  total  organic,  38 


ODOR,  determination  of,  2 
from  residue,  28 


River  water,  13,14,91,145,147 
Roll  culture,  69 


OALT,  action  on  boiler  waters,  m 
0     Samples,  collection  of,  21 
Sand  filters,  1 18 
Sanitary  application,  90 

examinations,  21 

Scale,  in 

Schuylkill  River  water,  composition  of, 


,  significance  of,  91 
Organic  matter,  16,  27,  90 

Sedgwick's  method,  62 
Sewage,  action  of,  18,  98 
Silica,  action  of,  in  water,  107 

,  precipitation  of,  123 

,  determination  of,  75 

Oxygen  consumed,  46 
-consuming  power,  46 
,  amount  of,  dissolved,  143 

Silicates,  action  on  lead,  107 
Silver  nitrate,  standard,  28 

,  dissolved,  determination  of,  51 

,  test  in  Porter's  process, 

,  dissolved,  effects  of,  100,  no 

132 

nitrite,  preparation  of,  45 

test  for  organic  matter,  50 

pARAMIDOBENZENE  -Sulphonic 

Sludge,  in 
Solids  total,  determination  of,  25 

*       acid,  44 
Parietti's  solution,  73 
Pasteur-Chamberlain  filter,  116 

Solids,  significance  of,  92 
Sodium  and  potassium,  separation   of, 

Permanganate  method,  46 

carbonate,  solution  of,  31,  39 

standard,  47,  49 

___^  standard    81 

Pettenkofer's  method  for  free  carbonic 

'  use   of,  in  boiler  waters, 

acid,  84 

Phenol  broth,  73 

chlorid,  standard,  28 

disulphonic  acid,  41 
Phenolphthalein,  use  of,  25 
Phosphates,  action  on  lead,  109 

,  determination  of,  79 
hydroxid,  solution,  39 
nitrite,  standard,  45 

,  determination  of,  51 

,  significance  of,  94 
,  use  of,  in  purifying  water,  131 

Source  of  water,  tracing  of,  132 
Smart,  C.,  nature  of  organic  matter,  96 

Plate  culture,  67 
Platinum,  preservation  of,  25 
Porter's   process   for    purifying   water, 

Specific  gravity,  87 
Spectroscope,  85 
Spectroscopic  examination,  85 

Potassium,  determination  of,  79 
chromate  solution,  28 

Spongy  iron  filters,  116 
Starch  indicator,  48 
Sterilizer  65 

iodid  solution.  41 

Storage,  effect  of,  122 

nitrate,  standard,  47 
Potassium  permanganate,  alkaline,  33 

Subsidence,  promotion  of,  15,  122 
Subsoil  water,  15,  144 

permanganate,  decinormal,  52 

Sulphanilic  acid,  44 

Potato  culture,  66 
Pure  water,  corrosive  action  of,  109 

Sulphids,  formation  of,  19,  92 
Sulphuretted   hydrogen,   determination 

Purification  of  boiler  water,  129 
of  drinking  waters,  114 

Sulphuric  acid,  diluted,  49 
.  standard,  81 

Surface   water,  composition   of,  13,  14, 

145,  147 

•D  AFTER'S  method,  62 

Suspended  matters,  14,  15 

^     Rain  water,  13,  95,  144 

Reaction,  24 

TASTE,  significance  of,  91 

Residue,  charring  of,  27 
Results,  statement  of,  89 

Technic  examinations,  109 
Tests  for  metals,  delicacy  of,  61 

154  INDEX. 

Tidy's  permanganate  process,  47  X7AUGHAN,  typhoid  fever  germ,  107 

Tidy  and  Frankland,  standard  of  purity,  v      Vegetable  matter,  28,  96 

oq  Vegetable  growth  in  water,  62 
— — — ,  Odling  and    Crookes,  lead  in 

water  107  \X7  ATER,  amount  of,  in  rocks,  16 

Tri-sodium  phosphate,  use  of,  for  pun-  VV      Wanklyn,  standards  of  purity,  97 

fication,  131  Whipple,  unit  measure,  136^ 

,  growth  of  microscopic  organisms, 

U^SiKKJSS.^0  WatCrS'  I01  ™&  l-tose-agar,  «37 
Urea,  decomposition  of,  95 

Urine  in  water,  95  7TNC,  detection  of,  56 

U.  S.  gallon,  89  ~ 


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MARSHALL.  Physiological  Diagrams.  Life  Size,  Colored. 
Eleven  Life-Size  Diagrams  (each  seven  feet  by  three  feet  seven 
inches).  Designed  for  Demonstration  before  the  Class. 

In  Sheets,  Unmounted,  $40.00;  Backed  with  Muslin  and  Mounted 
on  Rollers,  $60.00 ;  Ditto,  Spring  Rollers,  in  Handsome  Walnut  Wall 
Map  Case  (send  for  special  circular),  $100.00;  Single  Plates — Sheets, 
85.00  ;  Mounted,  $7.50.  Explanatory  Key,  .50.  Descriptive  circu- 
lar upon  application. 

POTTER.     Compend  of  Anatomy,  Including  Visceral  Anatomy. 

5th   Edition.     16   Lithographed  Plates    and  117  other  Illustrations. 

.80 ;  Interleaved,  $1.25 

WILSON.     Human  Anatomy,     nth  Edition.   429  Illustrations,  26 

Colored  Plates,  and  a  Glossary  of  Terms.  $5.00 

WINDLE.     Surface  Anatomy  and  Landmarks.     Colored  and 

other  Illustrations,     fust  Ready.  $1.00 

ANESTHETICS. 

BUXTON.     On  Anesthetics.    2d  Edition.     Illustrated.  $1.25 

TURNBULL.  Artificial  Anesthesia.  The  Advantages  and 
Accidents  of;  Its  Employment  in  the  Treatment  of  Disease  ;  Modes 
of  Administration;  Considering  their  Relative  Risks;  Tests  of 
Purity  ;  Treatment  of  Asphyxia ;  Spasms  of  the  Glottis :  Syncope, 
etc.  4th  Edition,  Revised.  54  Illustrations.  Just  Ready.  $2.50 


SUBJECT  CATALOGUE. 


BRAIN  AND  INSANITY. 

BLACKBURN.  A  Manual  of  Autopsies.  Designed  for  the  Use 
of  Hospitals  for  the  Insane  and  other  Public  Institutions.  Ten  full- 
page  Plates  and  other  Illustrations.  >i-25 

GOWERS.  Diagnosis  of  Diseases  of  the  Brain,  zd  Edition. 
Illustrated.  tl-5° 

HORSLEY.  The  Brain  and  Spinal  Cord.  The  Structure  and 
Functions  of.  Numerous  Illustrations.  $2.50 

HYSLOP.  Mental  Physiology.  Especially  in  Relation  to  Men- 
tal Disorders.  With  Illustrations.  $4.25 

LEWIS  (SEVAN).  Mental  Diseases  A  Text  Book  Having 
Special  Reference  to  the  Pathological  Aspects  of  Insanity.  18  Litho- 
graphic Plates  and  other  Illustrations.  New  Edition.  In  Press. 

MANN.  Manual  of  Psychological  Medicine  and  Allied 
Nervous  Diseases.  Their  Diagnosis,  Pathology,  Prognosis,  and 
Treatment,  including  their  Medico-Legal  Aspects  ;  with  chapter  on 
Expert  Testimony,  and  an  Abstract  of  the  Laws  Relating  to  the 
Insane  in  all  the  States  of  the  Union.  Illustrated.  $3-oo 

REGIS  Mental  Medicine.  Authorized  Translation  by  H.  M. 
BANNISTER,  M.D.  $2.00 

STEARNS.  Mental  Diseases.  Designed  especially  for  Medical 
Students  and  General  Practitioners.  With  a  Digest  of  Laws  of  the 
various  States  Relating  to  Care  of  Insane.  Illustrated. 

Cloth,  $2.75;  Sheep,  $3  25 

TUKE.  Dictionary  of  Psychological  Medicine.  Giving  the 
Definition,  Etymology,  and  Symptoms  of  the  Terms  used  in  Medical 
Psychology,  with  the  Symptoms,  Pathology,  and  Treatment  of  the 
Recognized  Forms  of  Mental  Disorders,  together  with  the  Law  of 
Lunacy  in  Great  Britain  and  Ireland.  Two  volumes  $10.00 

WOOD,  H.  C.    Brain  and  Overwork.  .40 

CHEMISTRY  AND  TECHNOLOGY. 

Special  Catalogue  of  Chemical  Books  sent  free  upon  application. 

ALLEN.  Commercial  Organic  Analysis.  A  Treatise  on  the 
Modes  of  Assaying  the  Various  Organic  Chemicals  and  Products 
Employed  in  the  Arts,  Manufactures,  Medicine,  etc.,  with  concise 
methods  for  the  Detection  of  Impurities,  Adulterations,  etc.  2d  Ed 
Vol.  I,  Vol.  II,  Vol.  Ill,  Part  I.  These  volumes  cannot  be  had. 
Vol.  Ill,  Part  II.  The  Amins  Pyridin  and  rls  Hydrozins  and 
Derivatives.  The  Antipyretics,  etc.  Vegetable  Alkaloids,  Tea, 
Coffee,  Cocoa,  etc.  $4.50 

Vol.  Ill,  Part  III.  Animal  Bases,  Animal  Acids,  Cyanogen  Com- 
pounds, Proteids,  etc.  $4-5° 
Vol.  Ill,  Part  IV.  The  Proteids  and  Albuminoids.  In  Press. 

ALLEN.  Chemical  Analysis  of  Albuminous  and  Diabetic 
Urine.  Illustrated.  $2.25 

BARTLEY.  Medical  and  Pharmaceutical  Chemistry.  A 
Text-Book  for  Medical,  Dental,  and  Pharmaceutical  Students.  With 
Illustrations,  Glossary,  and  Complete  Index.  4th  Edition,  carefully 
Revised.  Cloth,  $2.75 ;  Sheep,  $3.25 

BLOXAM.  Chemistry,  Inorganic  and  Organic.  With  Experi- 
ments. 8th  Ed.,  Revised  281  Engravings.  Clo.,$4.25;  Lea.,  $5. 25 

CALDWELL.  Elements  of  Qualitative  and  Quantitative 
Chemical  Analysis,  ^d  Edition,  Revised.  $1.50 


MEDICAL  BOOKS. 


CAMERON.     Oils  and  Varnishes.    With  Illustrations,  Formulae, 
Tables,  etc.  ja.aj 

CAMERON.    Soap  and  Candles.    54  Illustrations.  $2.00 

y  Qualitative    An- 

f Schools  and  Colleges. 


CLOWES  AND    COLEMAN.     Elementary  Qualitative    An- 
alysis.    Adapted  for  Use  in  the  Laboratories  of  Sc 
Illustrated.  . 

GARDNER.  The  Brewer,  Distiller,  and  Wine  Manufac- 
turer. A  Hand-Book  for  all  Interested  in  the  Manufacture  and 
Trade  of  Alcohol  and  Its  Compounds.  Illustrated.  $1.50 

GARDNER.    Bleaching,  Dyeing,  and  Calico  Printing.    With 

Formulae.     Illustrated.  $1.50 

GROVES  AND  THORP.  Chemical  Technology.  The  Appli- 
cation of  Chemistry  to  the  Arts  and  Manufactures.  8  Volumes, 
with  numerous  Illustrations. 

Vol.  I.   Fuel  and  Its  Applications.     607  Illustrations  and  4  Plates. 
Cloth,  $5.00;  Half  Morocco,  $6.  50 

Vol.11.   Lighting.      Illustrated.     Cloth,  $4.00;  Half  Morocco,  $5.50 
Vol.  III.  Lighting—  Continued.  In  Press. 

HOLLAND.  The  Urine,  the  Gastric  Contents,  the  Common 
Poisons,  and  the  Milk.  Memoranda,  Chemical  and  Microscopi- 
cal, for  Laboratory  Use.  5th  Ed.  Illustrated  and  interleaved,  $1.00 

LEFFMANN.    Compend    of    Medical    Chemistry,   Inorganic 

and  Organic.    Including  Urine  Analysis.     4th  Edition,  Rewritten. 

.80  ;  Interleaved,  $1.25 

LEFFMANN.  Progressive  Exercises  in  Practical  Chemis- 
try. Illustrated.  2d  Edition.  $1.00 

LEFFMANN.  Analysis  of  Milk  and  Milk  Products.  Arranged 
to  Suit  the  Needs  of  Analytical  Chemists,  Dairymen,  and  Milk  Inspec- 
tors. 2d  Edition.  Enlarged,  Illustrated.  $1-25 

LEFFMANN.     Water  Analysis.     Illustrated.    3d  Edition.    $1.25 

LEFFMANN.     Structural   Formulae   for  the  Use  of  Students. 

Including   180  Structural  and    Stereo-Chemical    Formulae.      i2mo. 

Interleaved.  Just  Ready.  $1.00 

MUTER.  Practical  and  Analytical  Chemistry.  4th  Edition. 

Revised  to  meet  the  requirements  ot  American  Medical  Colleges  by 

CLAUDE  C.  HAMILTON,  M.D.  51  Illustrations.  $1.25 

OETTEL.  Practical  Exercises  in  Electro-Chemistry.  Illus- 

trated. Nearly  Ready. 

OETTEL.  Introduction  to  Electro-Chemical  Experiments. 

Illustrated.  Nearly  Ready. 

RICHTER.  Inorganic  Chemistry.  4th  American,  from  6th  Ger- 

man  Edition.     Authorized  translation  by  EDGAR  F.   SMITH,  M.A., 

PH.D.  89  Illustrations  and  a  Colored  Plate.  >i-75 

RICHTER.  Organic  Chemistry.  3d  American  Edition.  Trans. 

from  the  last  German  by  EDGAR  F.  SMITH.  Illustrated.  /»  Press. 
SMITH.  Electro-Chemical  Analysis.  2d  Edition,  Revised.  28 

Illustrations.  $1.25 

SMITH  AND  KELLER.  Experiments.  Arranged  for  Students 

in  General  Chemistry.  3d  Edition.  Illustrated  .60 

STAMMER.  Chemical  Problems.  With  Explanations  and  An- 

swers. .50 


SUBJECT  CATALOGUE. 


SUTTON.  Volumetric  Analysis.  A  Systematic  Handbook  for 
the  Quantitative  Estimation  of  Chemical  Substances  by  Measure, 
Applied  to  Liquids,  Solids,  and  Gases  7th  Edition,  Revised.  112 
Illustrations,  fust  Ready.  $4.50 

SYMONDS.  Manual  of  Chemistry,  for  Medical  Students. 
2<i  Edition.  £2.00 

WATTS.  Organic  Chemistry.  2d  Edition.  By  WM.  A.  TILDEN, 
D.SC.,F.R.S.  (Being  the  i3th  Edition  of  Fowne's  Organic  Chemistry.) 
Illustrated.  $2  oo 

WATTS.  Inorganic  Chemistry.  Physical  and  Inorganic.  (Being 
the  i4th  Edition  of  Fowne's  Physical  and  Inorganic  Chemistry.) 
With  Colored  Plate  of  Spectra  and  other  Illustrations.  $2.00 

WOODY.  Essentials  of  Chemistry  and  Urinalysis.  4th 
Edition.  Illustrated.  In  Press. 

*»*  Special  Catalogue  of  Books  on  Chemistry  free  upon  application. 


CHILDREN. 

CAUTLIE.  Feeding  of  Infants  and  Young  Children  by  Nat- 
ural and  Artificial  Methods.  Just  Ready.  $2.00 

HALE.  On  the  Management  of  Children  in  Health  and  Dis- 
ease. -5° 

HATFIELD.  Compend  of  Diseases  of  Children.  With  a 
Colored  Plate,  ad  Edition.  80;  Interleaved,  $1.25 

MEIGS.  Infant  Feeding  and  Milk  Analysis.  The  Examination 
of  Human  and  Cow's  Milk,  Cream,  Condensed  Milk,  etc.,  and 
Directions  as  to  the  Diet  of  Young  Infants.  .50 

MONEY.  Treatment  of  Diseases  in  Children.  Including  the 
Outlines  of  Diagnosis  and  the  Chief  Pathological  Differences  Between 
Children  and  Adults,  ad  Edition.  $2.50 

POWER.  Surgical  Diseases  of  Children  and  their  Treat- 
ment by  Modern  Methods.  Illustrated.  $2.50 

STARR.  The  Digestive  Organs  in  Childhood.  The  Diseases  of 
the  Digestive  Organs  in  Infancy  and  Childhood.  With  Chapters  on 
the  Investigation  of  Disease  and  the  Management  of  Children.  2d 
Edition,  Enlarged.  Illustrated  by  two  Colored  Plates  and  numerous 
Wood  Engravings.  $2  oo 

STARR.  Hygiene  of  the  Nursery.  Including  the  General  Regi- 
men and  Feeding  of  Infants  and  Children,  and  the  Domestic  Manage- 
ment of  the  Ordinary  Emergencies  of  Early  Life,  Massage,  etc.  6th 
Edition.  25  Illustrations.  Just  Ready.  $1.00 

TAYLOR  AND  WELLS.  The  Diseases  of  Children.  Illus- 
trated. A  New  Text-Book.  Nearly  Ready. 


CLINICAL  CHARTS. 

GRIFFITH.  Graphic  Clinical  Chart.  Printed  in  three  colors. 
Sample  copies  free.  Put  up  in  loose  packages  of  fifty,. 50.  Price  to 
Hospitals,  500  copies,  $400;  1000  copies,  $7.50.  With  name  of 
Hospital  printed  on,  .50  extra. 

TEMPERATURE  CHARTS.  For  Recording  Temperature, 
Respiration,  Pulse,  Day  of  Disease,  Date,  Age,  Sex^  Occu- 
pation, Name,  etc.  Put  up  in  pads  of  fifty.  Each,  .50 


MEDICAL   BOOKS. 


DEFORMITIES. 

REEVES.      Bodily   Deformities   and    Their    Treatment.      A 

Hand-Book  of  Practical  Orthopedics.     228  Illustrations.  $1.75 

HEATH      Injuries  and  Diseases  of  the  Jaws.     187  Illustrations. 

4th  Edition.  Cloth,  $4.50 

DENTISTRY. 

Special  Catalogue  of  Dental  Books  sent  free  upon  application. 

BARRETT.  Dental  Surgery  for  General  Practitioners  and 
Students  of  Medicine  and  Dentistry.  Extraction  of  Teeth, 
etc.  3d  Edition.  Illustrated.  Nearly  Ready 

BLODGETT.  Dental  Pathology.  By  ALBERT  N.  BLODGBTT, 
M  D.,  late  Professor  of  Pathology  and  Therapeutics,  Boston  Dental 
College.  33  Illustrations.  $1.25 

FLAGG.  Plastics  and  Plastic  Filling,  as  Pertaining  to  the  Filling 
of  Cavities  in  Teeth  of  all  Grades  of  Structure.  4th  Edition.  $4.00 

FILLEBROWN.  A  Text-Book  of  Operative  Dentistry. 
Written  by  invitation  of  the  National  Association  of  Dental  Facul- 
ties. Illustrated.  $2.25 

GORGAS.  Dental  Medicine.  A  Manual  of  Materia  Medica  and 
Therapeutics,  sth  Edition,  Revised.  Cloth,  $4.00;  Sheep,  $5.00 

HARRIS.  Principles  and  Practice  of  Dentistry.  Including 
Anatomy,  Physiology,  Pathology,  Therapeutics,  Dental  Surgery, 
and  Mechanism.  1 3th  Edition.  Revised  by  F.  J.  S.  GORGAS,  M.D., 
D.D.S.  1250  Illustrations.  Cloth,  £6.00;  Leather,  $7.00 

HARRIS.  Dictionary  of  Dentistry.  Including  Definitions  of  Such 
Words  and  Phrases  of  the  Collateral  Sciences  as  Pertain  to  the  Art  and 
Practice  of  Dentistry,  sth  Edition.  Revised  and  Enlarged  by  FER- 
DINAND F.  S.  GORGAS,  M  D.,  D.D.S.  Cloth,  $4.50;  Leather,  $5.50 

HEATH.  Injuries  and  Diseases  of  the  Jaws,  4th  Edition  187 
Illustrations.  $4-5° 

HEATH.  Lectures  on  Certain  Diseases  of  the  Jaws.  64 
Illustrations.  Boards,  .50 

RICHARDSON.  Mechanical  Dentistry.  7th  Edition  Thor- 
oughly Revised  and  Enlarged  by  DR.  GKO.  W.  WARREN.  691  Illus- 
trations Just  Ready.  Cloth,  $5.00;  Leather,  $6.00 

SEWELL.  Dental  Surgery.  Including  Special  Anatomy  and 
Surgery.  3d  Edition,  with  200  Illustrations.  $200 

TAFT.  Operative  Dentistry.  A  Practical  Treatise,  sth  Edition, 
too  Illustrations.  In  Press. 

TAFT.    Index  of  Dental  Periodical  Literature.  $2.00 

TALBOT.  Irregularities  of  the  Teeth  and  Their  Treatment. 
2d  Edition  234  Illustrations.  13  °° 

TOMES.  Dental  Anatomy.  Human  and  Comparative.  235  Illus- 
trations. 4th  Edition.  t3-5° 

TOMES.     Dental  Surgery.  3d  Edition.     292  Illustrations.        $4.00 

WARREN.  Compend  of  Dental  Pathology  and  Dental  Medi- 
cine. With  a  Chapter  on  Emergencies.  Illustrated. 

.80;  Interleaved,  $1.25 

WARREN.  Dental  Prosthesis  and  Metallurgy.  129  Ills.  $1.25 

WHITE.     The  Mouth  and  Teeth.     Illustrated.  .4° 

%*  Special  Catalogue  of  Dental  Books  free  upon  application. 


SUBJECT   CATALOGUE. 


DICTIONARIES. 

GOULD.    The  Illustrated  Dictionary  of  Medicine,  Biology, 

and  Allied  Sciences.     Being  an  Exhaustive  Lexicon  of  Medicine 

and  those  Sciences  Collateral  to  it:    Biology  (Zoology  and  Botany), 

Chemistry,  Dentistry,  Parmacology,  Microscopy,  etc.,  with  many 

useful  Tables  and  numerous  fine  Illustrations.     1633  pages.     3d  Ed. 

Sheep  or  Half  Dark  Green  Leather,  $10.00;  Thumb  Index,  $11.00 

Half  Russia,  Thumb  Index,  $12.00 

GOULD.  The  Medical  Student's  Dictionary.  Including  all  the 
Words  and  Phrases  Generally  Used  in  Medicine,  wilh  their  Proper 
Pronunciation  and  Definition,  Based  on  Recent  Medical  Literature. 
With  Tables  of  the  Bacilli,  Micrococci,  Mineral  Springs,  etc.,  of  the 
Arteries,  Muscles,  Nerves,  Ganglia,  and  Plexuses,  etc.  loth  Edition. 
Rewritten  and  Enlarged.  Completely  reset  from  new  type  700  pp. 
Half  Dark  Leather,  $3.25 ;  Half  Morocco,  Thumb  Index,  $4.00 

GOULD.  The  Pocket  Pronouncing  Medical  Lexicon.  (12,000 
Medical  Words  Pronounced  and  Defined.)  Containing  all  the  Words, 
their  Definition  and  Pronunciation,  that  the  Medical,  Dental,  or 
Pharmaceutical  Student  Generally  Comes  in  Contact  With ;  also 
Elaborate  Tables  of  the  Arteries,  Muscles,  Nerves,  Bacilli,  etc.,  etc., 
a  Dose  List  in  both  English  and  Metric  System,  etc.,  Arranged  in  a 
Most  Convenient  Form  for  Reference  and  Memorizing. 

Full  Limp  Leather,  Gilt  Edges,  $1.00  ;  Thumb  Index,  $1.25 
60,000  Copies  of  Gould's  Dictionaries  Have  Been  Sold. 
*„,*  Sample  Pages   and    Illustrations  and    Descriptive   Circulars   of 

Gould's  Dictionaries  sent  free  upon  application. 

HARRIS.  Dictionary  of  Dentistry.  Including  Definitions  of  Such 
Words  and  Phrases  of  the  Collateral  Sciences  as  Pertain  to  the  Art 
and  Practice  of  Dentistry,  sth  Edition.  Revised  and  Enlarged  by 
FERDINAND  J.  S.  GORGAS,  M.D.,  D.D.S.  Cloth,  $4.50;  Leather,  $5.50 

LONGLEY.  Pocket  Medical  Dictionary.  With  an  Appendix, 
containing  Poisons  and  their  Antidotes,  Abbreviations  used  in  Pre- 
scriptions, etc.  Cloth,  .75  ;  Tucks  and  Pocket,  $1.00 

CLEVELAND.  Pocket  Medical  Dictionary.  33d  Edition.  Very 
small  pocket  size.  Cloth,  .50  ;  Tucks  with  Pocket,  .75 

MAXWELL.  Terminologia  Medica  Polyglotta.  By  Dr. 
THEODORE  MAXWELL,  Assisted  by  Others.  $3.00 

The  object  of  this  work  is  to  assist  the  medical  men  of  any  nationality 

In   reading  medical  literature  written   in  a  language  not   their  own. 

Each  term  is  usually  given  in  seven  languages,  viz. :  English,  French, 

German,  Italian,  Spanish,  Russian,  and  Latin. 

TREVES  AND  LANG.    German-English  Medical  Dictionary. 

Half  Russia,  $3.25 

EAR  (see  also  Throat  and  Nose). 

HOVELL.  Diseases  of  the  Ear  and  Naso-Pharynx.  Includ- 
ing Anatomy  and  Physiology  of  the  Organ,  together  with  the  Treat- 
ment of  the  Affections  of  the  Nose  and  Pharynx  which  Conduce  to 
Aural  Disease.  122  Illustrations.  $5-°° 

BURNETT.     Hearing  and  How  to  Keep  It.     Illustrated.          .40 

DALBY.  Diseases  and  Injuries  of  the  Ear.  4th  Edition.  38 
Wood  Engravings  and  8  Colored  Plates.  $2.50 

PRITCHARD.  Diseases  of  the  Ear.  3d  Edition,  Enlarged. 
Many  Illustrations  and  Formulae  Just  Ready.  $J-5° 

WOAKES.  Deafness,  Giddiness,  and  Noises  in  the  Head. 
4th  Edition.  Illustrated.  Just  Ready.  $2.00 


MEDICAL  BOOKS. 


ELECTRICITY. 

BIGELOW.      Plain  Talks  on  Medical  Electricity  and  Bat- 
teries.    With  a  Therapeutic   Index  and  a   Glossary.       43  Illustra- 
tions.    2d  Edition.  £1.00 
JONES.    Medical  Electricity.  2d  Edition.   112  Illustrations.    $2.50 
MASON.    Electricity ;  Its  Medical  and  Surgical  Uses.   Numer- 
ous  Illustrations.                                      .  .75 

EYE. 

A  Special  Circular  of  Books  on  the  Eye  tent  frte  upon  application. 

ARLT.  Diseases  of  the  Eye.  Clinical  Studies  on  Diseases  of  the 
Eye.  Authorized  Translation  by  LYMAN  WARE,  M.D.  Illustrated. 

$'•25 

PICK.  Diseases  of  the  Eye  and  Ophthalmoscopy.  Trans- 
lated by  A.  B.  HALB,  M.  D.  157  Illustrations,  many  of  which  are  in 
colors,  and  a  glossary.  Cloth,  $4.50  ;  Sheep,  $5.50 

GOULD  AND  PYLE.  Compend  of  Diseases  of  the  Eye  and 
Refraction.  Including  Treatment  and  Operations,  and  a  Section 
on  Local  Therapeutics.  With  Formula,  Useful  Tables,  a  Glossary, 
and  in  Illustrations,  several  of  which  are  in  colors.  Just  Ready. 

Cloth,  80;  Interleaved,  Ji.oo 

GOWERS.  Medical  Ophthalmoscopy.  A  Manual  and  Atlas 
with  Colored  Autotype  and  Lithographic  Plates  and  Wood-cuts, 
Comprising  Original  Illustrations  of  the  Changes  of  the  Eye  in  Dis- 
eases of  the  Brain,  Kidney,  etc.  sd  Edition.  $4.00 

HARLAN.    Eyesight,  and  How  to  Care  for  It.    Illus.  .40 

HARTRIDGE.  Refraction.  96  Illustrations  and  Test  Types. 
8th  Edition,  Enlarged.  $1.50 

HARTRIDGE.  On  the  Ophthalmoscope.  3d  Edition.  With 
72  Colored  Plates  and  many  Wood-cuts.  $1.50 

HANSELL  AND  BELL.  Clinical  Ophthalmology.  Colored 
Plate  of  Normal  Fundus  and  120  Illustrations.  Ji-5° 

MACNAMARA.  On  the  Eye.  sth  Edition.  Numerous  Colored 
Plates,  Diagrams  of  Eye,  Wood-cuts,  and  Test  Types.  fo-5° 

MORTON.  Refraction  of  the  Eye.  Its  Diagnosis  and  the  Cor- 
rection of  its  Errors.  With  Chapter  on  Keratoscopy  and  Test 
Types.  6th  Edition.  Ji.oo 

OHLEMANN.  Ocular  Therapeutics.  Authorized  Translation, 
and  Edited  by  DR.  CHARLES  A.  OLIVER.  In  Press. 

PHILLIPS.  Spectacles  and  Eyeglasses.  Their  Prescription 
and  Adjustment.  2d  Edition.  49  Illustrations.  |i.oo 

SWANZY.  Diseases  of  the  Eye  and  Their  Treatment.  6th 
Edition,  Revised  and  Enlarged.  158  Illustrations,  i  Plain  Plate, 
and  a  Zephyr  Test  Card  Just  Ready.  $3.00 

THORINGTON.     Retinoscopy.     Illustrated.    Just  Ready.    $1.00 

WALKER.  Students'  Aid  in  Ophthalmology.  Colored  Plate 
and  40  other  Illustrations  and  Glossary.  $i-5° 

FEVERS. 

COLLIE.  On  Fevers.  Their  History,  Etiology,  Diagnosis,  Prog- 
nosis, and  Treatment.  Colored  Plates.  >2.oo 

GOODALL  AND  WASHBOURN.  Fevers  and  Their  Treat- 
ment. Illustrated.  fe-°° 


SUBJECT  CATALOGUE. 


GOUT  AND  RHEUMATISM. 

DUCKWORTH.  A  Treatise  on  Gout.  With  Chromo-lithographs 
and  Engravings.  Cloth,  $6.00 

GARROD.  On  Rheumatism.  A  Treatise  on  Rheumatism  and 
Rheumatic  Arthritis.  Cloth,  $5.00 

HAIG.  Causation  of  Disease  by  Uric  Acid.  A  Contribution  to 
the  Pathology  of  High  Arterial  Tension,  Headache,  Epilepsy,  Gout, 
Rheumatism,  Diabetes,  Bright's  Disease,  etc.  $d  Edition.  $3-oo 


HEADACHES. 

DAY.    On   Headaches.     The   Nature,  Causes,   and  Treatment  ot 
Headaches.    4th  Edition      Illustrated.  Ji.oo 


HEALTH    AND     DOMESTIC    MEDI- 
CINE (see  also  Hygiene  and  Nursing). 

BUCKLEY.    The  Skin  in  Health  and  Disease.    Illus.  .40 

BURNETT.     Hearing  and  How  to  Keep  It.    Illustrated.  .40 

COHEN.     The  Throat  and  Voice.     Illustrated  .40 

DULLES.     Emergencies.    4th  Edition.     Illustrated.  fi.oo 
HARLAN.     Eyesight  and  How  to  Care  for  It.     Illustrated.     .40 

HARTSHORNE.     Our  Homes.     Illustrated.  .40 

OSGOOD.    The  Winter  and  its  Dangers.  .40 

PACKARD.    Sea  Air  and  Bathing.  .40 

PARKES.     The  Elements  of  Health.    Just  Ready.  $1.25 

RICHARDSON.    Long  Life  and  How  to  Reach  It.  .40 

WESTLAND.    The  Wife  and  Mother.  $1.50 

WHITE.    The  Mouth  and  Teeth.     Illustrated.  .40 

'WILSON.    The  Summer  and  its  Diseases.  .40 

WOOD.    Brain  Work  and  Overwork.  .40 

STARR.     Hygiene  of  the  Nursery,     sth  Edition.  $1.00 

CANFIELD.    Hygiene  of  the  Sick-Room.  $1.25 


HEART. 

SANSOM.  Diseases  of  the  Heart.  The  Diagnosis  and  Pathology 
of  Diseases  of  the  Heart  and  Thoracic  Aorta.  With  Plates  and  other 
Illustrations.  $6.00 


HISTOLOGY. 

nes  of  Practical  Histolo 
and  Enlarged.     With  new 
STOHR.     Histology  and  Microscopical  Anatomy.    Translated 
and  Edited  by  A.  SCHAPER,  M.D.,  Harvard  Medical  School.      268 


STIRLING.    Outlines  of  Practical  Histology.    368  Illustrations. 
zd  Edition,  Revised  and  Enlarged.     With  new  Illustrations.       $2. 


Illustrations. 


MEDICAL  BOOKS 


HYGIENE  AND  WATER  ANALYSIS. 

Special  Catalogue  of  Books  on  Hygiene  sent  free  upon  application. 

CANFIELD.  Hygiene  of  the  Sick-Room.  A  Book  for  Nurses 
and  Others  Being  a  Brief  Consideration  of  Asepsis,  Antisepsis,  Dis- 
infection, Bacteriology,  Immunity,  Heating  and  Ventilation,  and 
Kindred  Subjects.  t*-*5 

COPLIN  AND  SEVAN.  Practical  Hygiene.  A  Complete 
American  Text-Book.  138  Illustrations.  Cloth,  $3. 25  ;  Sheep,  $4. 25 

FOX.  Water,  Air,  and  Food.  Sanitary  Examinations  of  Water, 
Air,  and  Food.  100  Kngravings.  2d  Edition,  Revised.  $3*5° 

KENWOOD.  Public  Health  Laboratory  Work.  n6  Illustra- 
tions and  3  Plates.  $2.00 

LEFFMANN.  Examination  of  Water  for  Sanitary  and 
Technical  Purposes.  3d  Edition.  Illustrated.  $1-25 

LEFFMANN.  Analysis  of  Milk  and  Milk  Products.  Illus- 
trated. $1.25 

LINCOLN.     School  and  Industrial  Hygiene.  .40 

MACDONALD.  Microscopical  Examinations  of  Water  and 
Air.  25  Lithographic  Plates,  Reference  Tables,  etc.  2d  Ed.  $2.50 

McNEILL.  The  Prevention  of  Epidemics  and  the  Construc- 
tion and  Management  of  Isolation  Hospitals.  Numerous  Plans 
and  Illustrations.  $3-5° 

NOTTER  AND  FIRTH.  The  Theory  and  Practice  of  Hygiene. 
(Being  the  gth  Edition  of  Parkes'  Practical  Hygiene,  rewritten  and 
brought  up  to  date.)  10  Plates  and  135  other  Illustrations.  1034 
pages.  8vo.  Just  Ready,  $7-°° 

PARKES.  Hygiene  and  Public  Health.  By  Louis  C.  Parkes, 
M.D.  sth  Edition.  Enlarged.  Illustrated.  #2.50 

PARKES.  Popular  Hygiene.  The  Elements  of  Health.  A  Book 
for  Lay  Readers.  Illustrated.  $i.»5 

STARR.  The  Hygiene  of  the  Nursery.  Including  the  General 
Regimen  and  Feeding  of  Infants  and  Children,  and  the  Domestic 
Management  of  the  Ordinary  Emergencies  of  Early  Life,  Massage, 
etc.  6th  Edition.  25  Illustrations.  Just  Ready.  Ji.oo 

STEVENSON  AND  MURPHY.  A  Treatise  on  Hygiene.  By 
Various  Authors.  In  Three  Octave  Volumes.  Illustrated. 

Vol.  I,  $6.00;  Vol.  II,  £6.00;  Vol.  Ill,  $5.00 
***  Each  Volume  sold  separately.   Special  Circular  upon  application. 

WILSON.  Hand-Book  of  Hygiene  and  Sanitary  Science. 
With  Illustrations.  Sth  Edition.  Preparing. 

WEYL.  Sanitary  Relations  of  the  Coal-Tar  Colors.  Author- 
ized Translation  by  HENRY  LEFPMANN,  M.D.,  PH.D.  $1.25 

***  Special  Catalogue  of  Books  on  Hygiene  free  upon  application. 


JOURNALS,  ETC. 

OPHTHALMIC  REVIEW.  A  Monthly  Record  of  Ophthalmic 
Science.  Publ.  in  London.  Sample  number  .25 ;  per  annum  $3.00 

NEW  SYDENHAM  SOCIETY  PUBLICATION.  Three  to  six 
volumes  each  year.  Circular  upon  application.  Per  annum  fS.oc 


SUBJECT  CATALOGUE. 


KIDNEY  DISEASES. 

THORNTON.  The  Surgery  of  the  Kidney.  10  Illus.    Clo.,*i.so 

TYSON.     Bright's  Disease   and  Diabetes.     With  Especial  Ref- 

erence to  Pathology  and  Therapeutics.    Including  a  Section  on  Reti- 

nitis  in  Bright's  Disease.     New  Edition  In  Preparation 


LUNGS  AND  PLEURA. 

HARRIS  AND  BEALE.  Treatment  of  Pulmonary  Consump- 
tion. $2.50 

POWELL.  Diseases  of  the  Lungs  and  Pleurae,  including 
Consumption.  Colored  Plates  and  other  Illus.  4th  Ed.  $4.00 

TUSSEY.  High  Altitudes  in  the  Treatment  of  Consumption. 
fust  Ready.  $  1.50 

MASSAGE. 

KLEEN.  Hand-Book  of  Massage.  Authorized  translation  by 
MUSSBY  HARTWBLL,  M.D.,  PH.D.  With  an  Introduction  by  Dr.  S. 
WEIR  MITCHELL.  Illustrated  by  a  series  of  Photographs  Made 
Especially  by  DR.  KLEEN  for  the  American  Edition.  $2.25 

MURRELL.  Massotherapeutics.  Massage  as  a  Mode  of  Treat- 
ment. $th  Edition.  $1.25 

OSTROM.  Massage  and  the  Original  Swedish  Move- 
ments. Their  Application  to  Various  Diseases  of  the  Body.  A 
Manual  for  Students,  Nurses,  and  Physicians.  Third  Edition,  En- 
larged. 94  Wood  Engravings,  many  of  which  are  original.  $1.00 


MATERIA    MEDICA    AND    THERA- 
PEUTICS. 

ALLEN,  HARLAN,  HARTE,  VAN  HARLINGEN.  A 
Hand-Book  of  Local  Therapeutics,  Beinga  Practical  Description 
of  all  those  Agents  Used  in  the  Local  Treatment  of  Diseases  of  the 
Eye,  Ear,  Nose  and  Throat,  Mouth,  Skin,  Vagina,  Rectum,  etc., 
such  as  Ointments,  Plasters,  Powders,  Lotions,  Inhalations,  Supposi- 
tories, Bougies,  Tampons,  and  the  Proper  Methods  of  Preparing  and 
Applying  Them.  Cloth,  13.00 ;  Sheep,  $4.00 

BIDDLE.  Materia  Medica  and  Therapeutics.  Including  Dose 
List,  Dietary  for  the  Sick,  Table  of  Parasites,  and  Memoranda  of 
New  Remedies.  i3th  Edition,  Thoroughly  Revised  in  accord- 
ance with  the  new  U.  S.  P.  64  Illustrations  and  a  Clinical  Index. 
Cloth,  $4.00;  Sheep,  $5.00 

BRACKEN.  Outlines  of  Materia  Medica  and  Pharmacology.  By 
H.  M.  BRACKEN,  University  of  Minnesota.  $2.75 

DAVIS.    Materia  Medica  and  Prescription  Writing.        $1.50 

FIELD.     Evacuant  Medication.    Cathartics  and  Emetics.      $1.75 

GORQAS.  Dental  Medicine.  A  Manual  of  Materia  Medica  and 
Therapeutics  5th  Edition,  Revised.  $4.00 

HELLER.  Essentials  of  Materia  Medica,  Pharmacy,  and 
Prescription  Writing.  In  Press. 

MAYS.    Theine  in  the  Treatment  of  Neuralgia.     %  bound,  .50 


MEDICAL  BOOKS.  13 


NAPHEYS.  Modern  Therapeutics,  gth  Revised  Edition,  En- 
larged and  Improved.  In  two  handsome  volumes.  Edited  by  ALLEN 
J.  SMITH,  M.D.,  and  J  AUBREY  DAVIS,  M.D  . 

Vol.  I.  General  Medicine  and  Diseases  of  Children.  $4.00 

Vol.  II.  General  Surgery,  Obstetrics,  and  Diseases  of  Women.  $4.00 

POTTER.  Hand-Book  of  Materia  Medica,  Pharmacy,  and 
Therapeutics,  including  the  Action  of  Medicines,  Special  Therapeu- 
tics, Pharmacology,  etc.,  including  over  600  Prescriptions  and  For- 
mulae. 6th  Edition,  Revised  and  Enlarged.  With  Thumb  Index  in 
each  copy.  Cloth,  $4.50 ;  Sheep,  $5.50 

POTTER.  Compend  of  Materia  Medica,  Therapeutics,  and 
Prescription  Writing,  with  Special  Reference  to  the  Physiologi- 
cal Action  of  Drugs.  6m  Revised  and  Improved  Edition,  based  upon 
the  U.  S.  P.  1890.  .80;  Interleaved,  $1.25 

SAYRE.  Organic  Materia  Medica  and  Pharmacognosy.  An 
Introduction  to  the  Study  of  the  Vegetable  Kingdom  and  the  Vege- 
table and  Animal  Drugs.  Comprising  the  Botanical  and  Physical 
Characteristics,  Source,  Constituents,  and  Pharmacopeial  Prepara- 
tions. With  chapters  on  Synthetic  Organic  Remedies,  Insects  In- 
jurious to  Drugs,  and  Pharmacal  Botany.  A  Glossary  and  543  Illus- 
trations, many  of  which  are  original.  $4-°° 

WARING.  Practical  Therapeutics.  4th  Edition,  Revised  and 
Rearranged.  Cloth,  $2.00;  Leather,  $3.00 

WHITE  AND  WILCOX.  Materia  Medica,  Pharmacy,  Phar- 
macology, and  Therapeutics.  3d  American  Edition,  Revised  by 
REYNOLD  W.  WILCOX,  M.A.,  M  D.,  LL.D.  Clo.,  $2.75;  Lea.,  $3.25 


MEDICAL    JURISPRUDENCE     AND 
TOXICOLOGY. 

REESE.   Medicaljurisprudence  and  Toxicology.  A  Text-Book 
for   Medical   and   Legal    Practitioners  and  Students.     4th   Edition. 
Revised  by  HBNRY  LBFFMANN,  M.D.       Clo. ,$3.00;  Leather,  $3.50 
"  To  the  student  of  medical  jurisprudence  and  toxicology  it  is  in- 
valuable, as  it  is  concise,  clear,  and  thorough  in  every  respect."—  The 
American  Journal  of  the  Medical  Sciences. 

MANN.    Forensic  Medicine  and  Toxicology.    Illus.          $6.50 

MURRELL.      What   to    Do    in    Cases    of   Poisoning.      ?th 

Edition,  Enlarged.  $1.00 

TANNER.     Memoranda  of  Poisons.    Their  Antidotes  and  Tests. 

yth  Edition.  -75 

MICROSCOPY. 

BEALE.  The  Use  of  the  Microscope  in  Practical  Medicine. 
For  Students  and  Practitioners.with  Full  Directions  for  Examining  the 
Various  Secretions, etc.,  by  the  Microscope.  4th  Ed.  500  Illus.  $6.50 

BEALE.  How  to  Work  with  the  Microscope.  A  Complete 
Manual  of  Microscopical  Manipulation,  containing  a  Full  Description 
of  many  New  Processes  of  Investigation,  with  Directions  for  Examin- 
ing Objects  Under  the  Highest  Powers,  and  for  Taking  Photographs 
of  Microscopic  Objects,  sth  Edition.  400  Illustrations,  many  of 
them  colored.  $6.50 

CARPENTER.  The  Microscope  and  Its  Revelations.  7th 
Edition.  800  Illustrations  and  many  Lithographs.  $5-5° 


14  SUBJECT  CATALOGUE. 


LEE.      The    Microtomist's    Vade    Mecum.     A  Hand-Rook  ol 

Methods  of  Microscopical  Anatomy.    887  Articles.      4th  Edition, 

•     Enlarged.    Just  Ready.  $4.00 

M  ACDONALD.  Microscopical  Examinations  of  Water  and  Air. 
25  Lithographic  Plates,  Reference  Tables,  etc.  zd  Edition.  $2.50 

REEVES.  Medical  Microscopy,  including  Chapters  on  Bacteri- 
ology, Neoplasms,  Urinary  Examination,  etc.  Numerous  Illus- 
trations, some  of  which  are  printed  in  colors.  $2.50 

WETHERED.  Medical  Microscopy.  A  Guide  to  the  Use  of  the 
Microscope  in  Practical  Medicine.  100  Illustrations.  $2.00 

MISCELLANEOUS. 

BLACK.  Micro-Organisms.  The  Formation  of  Poisons.  A 
Biological  Study  of  the  Germ  Theory  of  Disease.  .75 

BURNETT.  Foods  and  Dietaries.  A  Manual  of  Clinical  Diet- 
etics. 2d  Edition.  £1-50 

GOULD.  Borderland  Studies.  Miscellaneous  Addresses  and 
Essays.  i2mo.  $2.00 

GOWERS.    The  Dynamics  of  Life.  .75 

HAIG.  Causation  of  Disease  by  Uric  Acid.  A  Contribution  to 
the  Pathology  of  High  Arterial  Tension,  Headache,  Epilepsy,  Gout, 
Rheumatism,  Diabetes,  Bright's  Disease,  etc.  3d  Edition.  $3.00 

HARE.     Mediastinal  Disease.     Illustrated  by  six  Plates         $2.00 

HEMMETER.  Diseases  of  the  Stomach  Their  Special  Path- 
ology, Diagnosis,  and  Treatment.  With  Sections  on  Anatomy,  Diet- 
etics, Surgery,  etc  ,  and  many  Illustrations.  Clo.  $6.00;  Sh.  $7.00 

HENRY.    A  Practical  Treatise  on  Anemia.          Half  Cloth,  .50 

LEFFMANN.  The  Coal-Tar  Colors.  With  Special  Reference  to 
their  Injurious  Qualities  and  the  Restrictions  of  their  Use.  A  Trans- 
lation of  THEODORE  WEYL'S  Monograph.  $1.25 

MARSHALL.     History  of  Woman's  Medical  College  of  Penn- 

TREVES. '  Physical  Education  :  Its  Effects,  Methods,  Etc.  .75 
LIZARS.    The  Use  and  Abuse  of  Tobacco.  .40 

PARRISH.  Alcoholic  Inebriety  from  a  Medical  Standpoint, 
with  Cases.  gi.oo 

ST.  CLAIR.     Medical  Latin.  Ji.oo 

NERVOUS  DISEASES. 

BEEVOR.  Diseases  of  the  Nervous  System  and  their  Treat- 
ment. In  Press. 

GOWERS.  Manual  of  Diseases  of  the  Nervous  System.  A 
Complete  Text-Book.  2d  Edition,  Revised,  Enlarged,  and  in  many 
parts  Rewritten.  With  many  new  Illustrations.  Two  volumes. 
Vol.  I.  Diseases  of  the  Nerves  and  Spinal  Cord.  Clo.  $3.00 ;  Sh.  £4.00 
Vol.  II.  Diseases  of  the  Brain  and  Cranial  Nerves ;  General  and 
Functional  Disease.  Cloth,  £4.00;  Sheep,  $5.00 

GOWERS.    Syphilis  and  the  Nervous  System.  fi.oo 

GOWERS.  Diagnosis  of  Diseases  of  the  Brain.  2d  Edition. 
Illustrated.  $i-5° 

GOWERS.  Clinical  Lectures.  A  New  Volume  of  Essays  on  the 
Diagnosis,  Treatment,  etc.,  of  Diseases  of  the  Nervous  System.  $2.00 

GOWERS.  Epilepsy  and  Other  Chronic  Convulsive  Diseases. 
2d  Edition.  In  Press 


MEDICAL  BOOKS. 


HORSLEY.  The  Brain  and  Spinal  Cord.  The  Structure  and 
Functions  of.  Numerous  Illustrations.  $2.50 

OBERSTEINER.    The  Anatomy  of  the  Central  Nervous  Or- 
gans.     A  Guide  to  the  Study  of  their  Structure  in   Health  and  Dis- 
ease.    198  Illustrations.  $5.50 
ORMEROD.     Diseases  of  the  Nervous  System.     66  Wood  En- 
gravings. fj.OO 
OSLER.     Cerebral  Palsies  of  Children.    A  Clinical  Study.    $2.00 
OSLER.    Chorea  and  Choreiform  Affections.  $2.00 
PRESTON.     Hysteria  and  Certain  Allied  Conditions.    Their 
Nature  and  Treatment.     Illustrated.    Just  Ready.                         $2.00 
THORBURN.     Surgery  of  the  Spinal  Cord.     Illustrated.     $4.00 
WATSON.     Concussions.  An  Experimental  Study  of  Lesions  Aris- 
ing from  Severe  Concussions.                                        Paper  cover,  $1.00 
WOOD.    Brain  Work  and  Overwork.  .40 

NURSING. 

Special  Catalogue  of  Books  for  Nurses  sent  free  upon  application. 

BROWN.     Elementary  Physiology  for  Nurses.  .75 

CANFIELD.  Hygiene  of  the  Sick-Room.  A  Book  for  Nurses  and 
Others.  Being  a  Brief  Consideration  of  Asepsis,  Antisepsis,  Disinfec- 
tion. Bacteriology,  Immunity,  Heating  and  Ventilation,  and  Kindred 
Subjects  for  the  Use  of  Nurses  and  Other  Intelligent  Women.  $1.25 

CULLINGWORTH.  A  Manual  of  Nursing,  Medical  and  Sur- 
gical. 3d  Edition  with  Illustrations.  .75 

CULLINGWORTH.  A  Manual  for  Monthly  Nurses.  3dEd.  .40 

CUFF.     Lectures  to  Nurses  on  Medicine.  25  Illustrations.  Ji.oo 

DOMVILLE.  Manual  for  Nurses  and  Others  Engaged  in  At- 
tending the  Sick.  8th  Edition.  With  Recipes  for  Sick-room  Cook- 
ery, etc.  .75 

FULLERTON,     Obstetric  Nursing.    40  Ills.    4th  Ed.          $1.00 

FULLERTON.  Nursing  in  Abdominal  Surgery  and  Diseases 
of  Women.  Comprising  the  Regular  Course  of  Instruction  at  the 
Training-School  of  the  Women's  Hospital,  Philadelphia.  2d  Edition. 
70  Illustrations.  $i-5° 

HUMPHREY.  A  Manual  for  Nurses.  Including  General 
Anatomy  and  Physiology,  Management  of  the  Sick-Room,  etc.  isth 
Edition.  Illustrated.  fi.oo 

SHA  WE.  Notes  for  Visiting  Nurses,  and  all  those  Interested 
in  the  Working  and  Organization  of  District,  Visiting,  or 
Parochial  Nurse  Societies.  With  an  Appendix  Explaining  the 
Organization  and  Working  of  Various  Visiting  and  District  Nurse  So- 
cieties, by  HELEN  C.  JENKS,  of  Philadelphia.  $1.00 

STARR.  The  Hygiene  of  the  Nursery.  Including  the  General 
Regimen  and  Feeding  of  Infants  and  Children,  and  the  Domestic  Man- 
agement of  the  Ordinary  Emergencies  of  Early  Life,  Massage,  etc.  6th 
Edition.  25  Illustrations.  Just  Ready.  $1.00 

TEMPERATURE  CHARTS.  For  Recording  Temperature,  Res- 
piration, Pulse,  Day  of  Disease,  Date,  Age,  Sex,  Occupation, 
Name,  etc.  Put  up  in  pads  of  fifty.  Each  .50 

VO6WINKEL.  Surgical  Nursing.  HI  Illustrations.  $1.00 

%»  Special  Catalogue  of  Books  OH  N»rri*ffret  upon  application. 


SUBJECT  CATALOGUE. 


OBSTETRICS. 

BAR.  Antiseptic  Midwifery.  The  Principles  of  Antiseptic  Meth- 
ods Applied  to  Obstetric  Practice.  Authorized  Translation  by 
HENRY  D.  FRY,  M.D..  with  an  Appendix  by  the  Author.  $1.00 

CAZEAUX  AND  TARNIER.  Midwifery.  With  Appendix  by 
MuNDft.  The  Theory  and  Practice  of  Obstetrics,  including  the  Dis- 
eases of  Pregnancy  and  Parturition,  Obstetrical  Operations,  etc. 
8th  Edition.  Illustrated  by  Chromo-Lithographs,  Lithographs,  and 
Other  full-page  Plates,  seven  of  which  are  beautifully  colored,  and 
numerous  Wood  Engravings.  Cloth,  $4.50  ;  Full  Leather,  $5.50 

DAVIS.  A  Manual  of  Obstetrics.  Being  a  Complete  Manual  for 
Physicians  and  Students,  ad  Edition.  16  Colored  and  other  Plates 
and  134  other  Illustrations.  £2.00 

JELLETT.    The  Practice  of  Midwifery.     Illustrated.  $1.75 

LANDIS.  Compend  of  Obstetrics,  sth  Edition,  Revised  by  WM. 
H.  WELLS,  Assistant  Demonstrator  of  Clinical  Obstetrics,  Jefferson 
Medical  College.  With  many  Illustrations,  80;  Interleaved,  $1.25. 

SCHULTZE.  Obstetrical  Diagrams.  Being  a  series  of  20  Col- 
ored Lithograph  Charts,  Imperial  Map  Size,  of  Pregnancy  and  Mid- 
wifery, with  accompanying  explanatory  (German)  text  illustrated 
by  Wood  Cuts.  2d  Revised  Edition.  ' 

Price  in  Sheets,  £26.00  ;  Mounted  on  Rollers,  Muslin  Backs,  $36.00 

STRAHAN.  Extra-Uterine  Pregnancy.  The  Diagnosis  and 
Treatment  of  Extra-Uterine  Pregnancy.  .75 

WINCKEL.  Text-Book  of  Obstetrics,  Including  the  Pathol- 
ogy and  Therapeutics  of  the  Puerperal  State.  Authorized 
Translation  by  J.  CLIFTON  EDGAR,  A.M.,  M.D.  With  nearly  200  Illus- 
trations. Cloth,  $5.00;  Leather,  $6.00 

FULLERTON.    Obstetric  Nursing.     4th  Ed.    Illustrated.    Ji.oo 

SHIB  ATA.  Obstetrical  Pocket-Phantom  with  Movable  Child 
and  Pelvis.  Letter  Press  and  Illustrations.  |i.oo 

PATHOLOGY. 

BLACKBURN.  Autopsies.  A  Manual  of  Autopsies  Designed  for 
the  Use  oi  Hospitals  for  the  Insane  and  other  Public  Institutions. 
Ten  full-page  Plates  and  other  Illustrations.  $1.25 

BLODGETT.  Dental  Pathology.  By  ALBERT  N.  BLODGBTT, 
M  D.,  late  Professor  of  Pathology  and  Therapeutics,  Boston  Dental 
College.  33  Illustrations.  .  $1-25 

GILLIAM.     Pathology.  A  Hand-Book  for  Students.  47  Illus.     .75 

HALL.  Compend  of  General  Pathology  and  Morbid  Anatomy. 
91  very  fine  Illustrations.  .80  ;  Interleaved,  $1.25 

VIRCHOW.  Post-Mortem  Examinations.  A  Description  and 
Explanation  of  the  Method  of  Performing  Them  in  the  Dead  House 
of  the  Berlin  Charity  Hospital,  with  Special  Reference  to  Medico- 
Legal  Practice.  3d  Edition,  with  Additions.  .75 

WHITACRE.  Laboratory  Text-Book  of  Pathology.  With 
many  Illustrations.  /»  Press. 

PHARMACY. 

Special  Catalogue  of  Books  on  Pharmacy  sent  free  upon  application. 
COBLENTZ.      Manual   of  Pharmacy.      A   New  and  Complete 

Text-Book  by  the  Professor  in  the  New  York  College  of  Pharmtcy. 

2d  Edition,  Revised  and  Enlarged.  437  Illus.  Cloth,  $3.50 ;  Sh.,  $4  50 


MEDICAL   ROOKS.  17 


BEASLEY.  Book  of  3100  Prescriptions.  Collected  from  the 
Practice  of  the  Most  Eminent  Physicians  and  Surgeons— English, 
French,  and  American.  A  Compendious  History  ot  the  Materia 
Medica,  Lists  of  the  Doses  of  all  the  Officinal  and  Established  Pre- 
parations, an  Index  of  Diseases  and  their  Remedies.  7th  Ed.  $2.00 

BEASLEY.  Druggists'  General  Receipt  Book.  Comprising 
a  Copious  Veterinary  Formulary,  Recipes  in  Patent  and  Proprietary 
Medicines,  Druggists'  Nostrums,  etc. ;  Perfumery  and  Cosmetics, 
Beverages,  Dietetic  Articles  and  Condiments,  Trade  Chemicals, 
Scientific  Processes,  and  an  Appendix  of  Useful  Tables.  loth  Edi- 
tion, Revised.  $2.00 

BEASLEY.  Pocket  Formulary.  A  Synopsis  of  the  British  and 
Foreign  Pharmacopoeias.  Comprising  Standard  and  Approved 
Formulas  for  the  Preparations  and  Compounds  Employed  in  Medical 
Practice,  nth  Edition.  $2.00 

PROCTOR.  Practical  Pharmacy.  Lectures  on  Practical  Phar- 
macy. With  Wood  Engravings  and  32  Lithographic  Fac-simile 
Prescriptions.  3d  Edition,  Revised,  and  with  Elaborate  Tables  of 
Chemical  Solubilities,  etc.  fe.oo 

ROBINSON.  Latin  Grammar  of  Pharmacy  and  Medicine. 
2d  Edition.  With  elaborate  Vocabularies.  $1.75 

SAYRE.  Organic  Materia  Medica  and  Pharmacognosy.  An 
Introduction  to  the  Study  of  the  Vegetable  Kinedom  and  the  Vege- 
table and  Animal  Drugs.  Comprising  the  Botanical  and  Physical 
Characteristics,  Source,  Constituents,  and  Pharmacopeia!  Prepar- 
.  With  Chapters  on  Synthetic  Organic  Remedies,  Insects 
jus  to  Drugs,  and  Pharmacal  Botany.  A  Glossary  and  543 
.tions,  many  of  which  are  original.  Cloth,  £4.00;  Sheep,  $5.00 

SCOVILLE.  The  Art  of  Compounding.  A  Text-Book  for  the 
Student  and  a  Reference  Book  for  the  Pharmacist.  Cl.  $2.50 ;  Sh.  $3.50 

STEWART.  Compend  of  Pharmacy.  Based  upon  "  Reming- 
ton's Text-Book  of  Pharmacy  "  sth  Edition,  Revised  in  Accord- 
ance with  the  U.  S.  Pharmacopoeia,  1890.  Complete  Tables  of 
Metric  and  English  Weights  and  Measures.  .80;  Interleaved,  $1.25 

UNITED  STATES  PHARMACOPOEIA.  1890.  7th  Decennial 
Revision.  Cloth,  $2. 50  (postpaid,  $2.77)  ;  Sheep,  $3.00  (postpaid, 
$3.27);  Interleaved,  $4. oo  (postpaid,  $4.50);  Printed  on  one  side  ot 
page  only,  unbound,  $3.50  (postpaid,  £3.90) 

Select  Tables  from  the  U.  S.  P.  (1890).  Being  Nine  oJ  the  Most 
Important  and  Useful  Tables,  Printed  on  Separate  Sheets.  Care- 
fully put  up  in  patent  envelope.  .25 

POTTER.  Hand-Book  of  Materia  Medica,  Pharmacy,  and 
Therapeutics.  600  Prescriptions  and  Formulae.  6th  Edition. 

Cloth,  $4  50 ;  Sheep,  $5.50 

***  Special  Catalogue  of  Books  on  Pharmacy  free  upon  application. 


Injurious 
Illustrati 


PHYSICAL  DIAGNOSIS. 

FENWICK.  Medical  Diagnosis.  Sth  Edition.  Rewritten  and 
very  much  Enlarged.  135  Illustrations.  Cloth,  $2.50 

TYSON.  Hand-Book  of  Physical  Diagnosis.  For  Students  and 
Physicians  By  the  Professor  of  Clinical  Medicine  in  the  University 
of  Pennsylvania.  Illus.  2d  Ed.,  Improved  and  Enlarged.  $1.25 

MEMMINGER.  Diagnosis  by  the  Urine.  23  Illus.  fx.oo 

2 


18  SUBJECT  CATALOGUE. 

PHYSIOLOGY. 

BRUBAKER.  Compend  of  Physiology.  8th  Edition,  Revised 
and  Enlarged.  Illustrated.  .80;  Interleaved,  $i. 25 

KIRKE.    Physiology.    (i4th  Authorized  Edition.    Dark-Red  Cloth.) 

A  Hand-Book  of  Physiology.     Mth  Edition,  Revised  and  Enlarged. 

By  PROF.   W.   D    HALLIBURTON,  of  Kings  College,  London.    661 

Illustrations,  some  of    which  are  printed  in  colors.     Just  Ready. 

Cloth,  $3.25 ;  Leather,  $4.00 

LANDOIS.  A  Text-Book  of  Human  Physiology,  Including 
Histology  and  Microscopical  Anatomy,  with  Special  Reference  to 
the  Requirements  of  Practical  Medicine.  $th  American,  translated 
from  the  gth  German  Edition,  with  Additions  by  WM.  STIRLING, 
M  D..D.SC.  845  lllus.,  many  of  which  are  printed  in  colors.  In  Press. 

STARLING.     Elements  of  Human  Physiology.     100  Ills.    $1.00 

STIRLING.  Outlines  of  Practical  Physiology.  Including 
Chemical  and  Experimental  Physiology,  with  Special  Reference  to 
Practical  Medicine.  3d  Edition.  289  Illustrations.  $2.00 

TYSON.     Cell  Doctrine.    Its  History  and  Present  State.        $1.50 

YEO.  Manual  of  Physiology.  A  Text-Book  for  Students  of 
Medicine.  By  GERALD  F.  YEO,  M.D.,  F.R.C.S.  6th  Edition.  254 
Illustrations  and  a  Glossary.  Cloth,  $2.50  ;  Leather,  $3.00 

PRACTICE. 

BEALE.    On  Slight  Ailments;  their  Nature  and  Treatment. 

2d  Edition,  Enlarged  and  Illustrated.  $1.25 

CHARTERIS.     Practice  of  Medicine.    6th  Edition.  $2.00 

FOWLER.      Dictionary  of   Practical    Medicine.      By  various 

writers.  An  Encyclopedia  of  Medicine.  Clo.,$3.oo;   Half  Mor.  $400 

HUGHES.    Compend  of  the  Practice  of  Medicine.    sth  Edition, 

Revised  and  Enlarged. 

Part  I.  Continued,  Eruptive,  and  Periodical  Fevers,  Diseases  of  the 
Stomach,  Intestines,  Peritoneum,  Biliary  Passages,  Liver,  Kid- 
neys, etc.,  and  General  Diseases,  etc. 

Part  II.  Diseases  of  the  Respiratory  System,  Circulatory  System, 
and  Nervous  System;  Diseases  of  the  Blood,  etc. 

Price  of  each  part,  .80;  Interleaved,  $1.25 

Physician's  Edition.  In  one  volume,  including  the  above  two 
parts,  a  Section  on  Skin  Diseases,  and  an  Index  sth  Revised, 
Enlarged  Edition.  568  pp.  Full  Morocco,  Gilt  Edge,  $2.25 

ROBERTS.  The  Theory  and  Practice  of  Medicine.  The 
Sections  on  Treatment  are  especially  exhaustive,  gth  Edition, 
with  Illustrations.  Cloth,  $4.50;  Leather,  $5.50 

TAYLOR.     Practice  of  Medicine.  Cloth,  $2.00 ;  Sheep,  $2.50 

TYSON.  The  Practice  of  Medicine.  By  JAMES  TYSON,  M.D., 
Professor  of  Clinical  Medicine  in  the  University  of  Pennsylvania. 
A  Complete  Systematic  Text-book  with  Special  Reference  to  Diag- 
nosis and  Treatment.  Illustrated.  8vo.  Just  Ready. 

Cloth,  $5.50  ;  Leather,  $6  50  ;  Half  Russia,  $7.50 

PRESCRIPTION  BOOKS. 

BEASLEY.  Book  of  3100  Prescriptions.  Collected  from  the 
Practice  of  the  Most  Eminent  Physicians  and  Surgeons — English, 
French,  and  American.  A  Compendious  History  of  the  Materia, 
Medica,  Lists  of  the  Doses  of  all  Officinal  and  Established  Prepara- 
tions, and  an  Index  of  Diseases  and  their  Remedies.  7th  Ed.  $2.00 


MEDICAL  BOOKS.  19 


BEASLEY.  Druggists'  General  Receipt  Book.  Comprising 
SL  Copious  Veterinary  Formulary,  Recipes  in  Patent  and  Proprie- 
tary Medicines,  Druggists'  Nostrums,  etc.  ;  Perfumery  and  Cos- 
metics, Beverages,  Dietetic  Articles  and  Condiments,  Trade  Chem- 
icals, Scientific  Processes,  and  an  Appendix  of  Useful  Tables, 
loth  Edition,  Revised.  $2.00 

BEASLEY.  Pocket  Formulary.  A  Synopsis  of  the  British  and 
Foreign  Pharmacopoeias.  Comprising  Standard  and  Approved 
Formulae  for  the  Preparations  and  Compounds  Employed  in  Medical 
Practice,  nth  Edition.  Cloth,  $2.00 

PEREIRA.  Prescription  Book.  Containing  Lists  of  Phrases 
and  Abbreviations  Used  in  Prescriptions,  Grammatical  Construction 
of  Prescriptions,  etc.  i6th  Edition.  Cloth,  .75  ;  Tucks,  $1.00 

WYTHE.     Dose  and  Symptom  Book.    Containing  the  Doses  and 

Uses  of  all  the  Principal  Articles  of  the  Materia  Medica.     i7th  Ed. 

Cloth,  .75  ;  Leather,  with  Tucks  and  Pocket,  Ji.oo 

SKIN. 

BULKLEY.    The  Skin  in  Health  and  Disease.    Illustrated.    .40 
CROCKER.     Diseases  of  the  Skin.     Their  Description,  Pathol- 
ogy, Diagnosis,  and  Treatment,  with  Special  Reference  to  the  Skin 
Eruptions  of  Children.   92  Illus.   2d  Edition.   Cloth,  $4. 50 ;  Sh.,  $5. 50 
IMPEY.     Leprosy.     37  Plates.     8vo.  $3-5° 

SCHAMBERG.  Diseases  of  the  Skin.  Illustrated.  Being  No. 
16  ?  Quiz-Compend  ?  Series.  Cloth,  .80 ;  Interleaved,  $1.25 

VAN  HARLINGEN.  On  Skin  Diseases.  A  Practical  Manual 
of  Diagnosis  and  Treatment,  with  special  reference  to  Differential 
Diagnosis.  3d  Edition,  Revised  and  Enlarged.  With  Formulae 
and  60  Illustrations,  some  of  which  are  printed  in  colors.  J>2-75 

SURGERY  AND  SURGICAL  DIS- 
EASES. 

CAIRD  AND  CATHCART.  Surgical  Hand-Book.  sth  Edition, 
Revised.  188  Illustrations.  Full  Red  Morocco,  $2.50 

DEAVER.  Appendicitis,  Its  Symptoms,  Diagnosis,  Pathol- 
ogy, Treatment,  and  Complications.  Elaborately  Illustrated 
with  Colored  Plates  and  other  Illustrations.  Cloth,  $3.50 

DEAVER.  Surgical  Anatomy.  With  200  Illustrations,  Drawn  by  a 
Special  Artist  from  Directions  made  for  the  Purpose.  In  Preparation. 

DULLES.  What  to  Do  First  in  Accidents  and  Poisoning. 
5th  Edition.  New  Illustrations.  Ji.oo 

HACKER.  Antiseptic  Treatment  of  Wounds,  Introduction  to 
the,  According  to  the  Method  in  Use  at  Professor  Billroth  s  Clinic, 
Vienna.  With  a  Photo-engraving  of  Billroth  in  his  Clinic.  .50 

HEATH.  Minor  Surgery  and  Bandaging.  loth  Ed  Revised 
and  Enlarged.  158  Illustrations,  62  Formulae,  Diet  List,  etc  $1.25 

HEATH.  Injuries  and  Diseases  of  the  Jaws.  4th  Edition. 
187  Illustrations.  $4-5° 

HEATH.  Lectures  on  Certain  Diseases  of  the  Jaws.  64  Illus- 
trations. Boards,  .50 

HORWITZ.  Compend  of  Surgery  and  Bandaging,  including 
Minor  Surgery,  Amputations,  Fractures,  Dislocations,  Surgical  Dis- 
eases, and  the  Latest  Antiseptic  Rules,  etc.,  with  Differential  Diagno- 
sis and  Treatment,  sth  Edition,  very  much  Enlarged  and  Rear- 
ranged 167  Illustrations,  98  Formulae.  Clo.,  .80 ;  Interleaved,  $1.25 


SUBJECT  CATALOGUE. 


JACOBSON.    Operations    of   Surgery.    Over  200  Illustrations. 

Cloth,  $3.00;   Leather,  $4.00 

JACOBSON.    Diseases  of  the   Male   Organs  of  Generation. 

88   Illustrations.  $6.00 

MACREADY.     A  Treatise    on    Ruptures.     24    Full-page   Litho- 
graphed Plates  and  Numerous  Wood  Engravings.  Cloth,  $6.00 
MAYLARD.   Surgery  of  the  Alimentary  Canal.    134  Illus.  $7.50 
MOULLIN.     Text-Book  of  Surgery.     With  Special  Reference  to 
Treatment.     3d  American  Edition.     Revised  and  edited  by  JOHN  B. 
HAMILTON,  M.D.,  I.L.D.,  Professor  of  the  Principles  of  Surgery  and 
Clinical  Surgery,  Rush  Medical  College,  Chicago.     623  Illustrations, 
over  200  of  which  are  original,  and  many  of  which  are  printed  in 
colors.                                          Handsome  Cloth,  |6  oo ;   Leather,  $7.00 
"  The  aim  to  make  this  valuable  treatise  practical  by  giving  special 
attention  to   questions  of  treatment  has  been  admirably  carried  out. 
Many  a  reader  will  consult  the  work  with  a  feeling  of  satisfaction  that 
his  wants  have  been  understood,  and  that  they  have  been  intelligently 
met."—  The  American  Journal  of  Medical  Science. 
SMITH.     Abdominal  Surgery.     Being  a  Systematic  Description  o! 
all  the  Principal  Operations.    224  Illus.  sth  Ed.    2  Vols.  do.,  $10.00 
SWAIN      Surgical  Emergencies.     Fifth  Edition.         Cloth,  $i. 75 
VOSWINKEL.     Surgical  Nursing,     in  Illustrations.  $1.00 
WALSHAM.     Manual    of    Practical    Surgery.      5th    Ed.,    Re- 
vised and  Enlarged.     With  380  Engravings,    do.,  $2.00;   Lea.,  $2.50 
WATSON.    On  Amputations  of  the  Extremities   and  Their 
Complications.     250  Illustrations.  $5-5° 

THROAT   AND    NOSE   (see  also  Ear). 
COHEN.     The  Throat  and  Voice.     Illustrated.  .40 

HALL.      Diseases    of   the    Nose    and    Throat.     Two    Colored 

Plates  and  59  Illustrations  $2.50 

HUTCHINSON.     The  Nose  and  Throat.     Including  the   Nose, 

Naso- Pharynx,  Pharynx,  and   Larynx.     Illustrated  by    Lithograph 

Plates  and  40  other  Illustrations.     2d  Edition.  In  Press. 

MACKENZIE.    The  Pharmacoposia  of  the  London  Hospital 

for  Diseases  of  the  Throat,      sth    Edition,    Revised  by  Ur.  F. 

G.  HARVKY  $100 

McBRIDE.   Diseases  of  the  Throat,  Nose,  and  Ear.   A  Clinical 

Manual.    With  colored  Illus   from  original  drawings.   2d  Ed.      $6.00 
POTTER.     Speech  and  its  Defects.    Considered  Physiologically, 

Pathologically,  and  Remedially.  $1.00 

WOAKES.    Post-Nasal  Catarrh   and   Diseases  of  the   Nose 

Causing  Deafness.     26  Illustrations.  Ji.oo 


URINE  AND  URINARY  ORGANS. 

ACTON.     The  Functions  and  Disorders  of  the  Reproductive 

Organs  in  Childhood,  Youth,  Adult  Age,  and  Advanced  Life, 

Considered   in  their    Physiological,    Social,  and    Moral    Relations. 

Sth  Edition.  $1.75 

ALLEN.     Albuminous  and  Diabetic  Urine.     Illus.  $2.25 

BROCKBANK.    Gall  Stones.  $2.25 


MEDICAL  BOOKS 


BEALE.     One   Hundred   Urinary  Deposits.     On  eight  sheets, 
for  the  Hospital,  Laboratory,  or  Surgery.  Paper,  $2.00 

HOLLAND.    The  Urine,  the  Gastric  Contents,  the  Common 
Poisons,  and  the  Milk.     Memoranda,  Chemical  and  Microscopi- 
cal, for  Laboratory  Use.    Illustrated  and  Interleaved.    $th  Ed.  $1.00 
LEGG.     On  the  Urine.     ?th  Edition,  Enlarged.     Illus.  $1.00 

MEMMINGER.    Diagnosis  by  the  Urine.    23  Illus.  $1.00 

MOULLIN.     Enlargement  of  the  Prostate.     Its  Treatment  and 
Radical  Cure.     Illustrated.  $1.50 

THOMPSON.    Diseases  of  the  Urinary  Organs.   8th  Ed.  $3.00 
TYSON.     Guide  to   Examination  of  the  Urine.     For  the  Use  of 
Physicians  and  Students.     With  Colored  Plate  and  Numerous  Illus- 
trations engraved  on  wood,     gth  Edition,  Revised.  $1-25 
VAN   NUYS.     Chemical  Analysis  of  Healthy   and   Diseased 
Urine,  Qualitative  and  Quantitative.    39  Illustrations.       $1.00 


VENEREAL  DISEASES. 

COOPER.     Syphilis,     ad     Edition,   Enlarged  and   Illustrated   with 

20  full-page  Plates.  $5-oo 

GOWERS.    Syphilis  and  the  Nervous  System.  i  oo 

JACOBSON.    Diseases  of  the  Male  Organs  of  Generation.    88 

Illustrations.  #6.00 

VETERINARY. 

ARMATAGE.  The  Veterinarian's  Pocket  Remembrancer. 
Being  Concise  Directions  for  the  Treatment  of  Urgent  or  Rare  Cases, 
Embracing  Semeiology,  Diagnosis,  Prognosis,  Surgery,  Treatment, 
etc.  ad  Edition.  Boards ,$i  .00 

BALLOU.  Veterinary  Anatomy  and  Physiology.  29  Graphic 
Illustrations.  .80;  Interleaved,  $1.25 

TUSON.  Veterinary  Pharmacopoeia.  Including  the  Outlines  of 
Materia  Medica  and  Therapeutics,  sth  Edition.  $2.25 


WOMEN,  DISEASES  OF. 

BYFORD  (H.  T.).  Manual  of  Gynecology.  Second  Edition, 
Revised  and  Enlarged  by  100  pages.  With  341  Illustrations,  many 
of  which  are  from  original  drawings.  Just  Ready.  $3  oo 

BYFORD  (W.  H.).  Diseases  of  Women.  4th  Edition.  306 
Illustrations.  Cloth,  $2.00 

DiiHRSSEN.  A  Manual  of  Gynecological  Practice.  105 
Illust 


LEWERS.     Diseases  of  Women.     146  Illus.    sth  Ed.    In  Press. 

WELLS.  Compend  of  Gynecology.  Illus.  .80;  Interleaved,  $1.25 

WINCKEL.  Diseases  of  Women.  Translated  by  special  authority 
of  Author,  under  the  Supervision  of,  and  with  an  Introduction  by, 
THEOPHILUS  PARVIN,  M.D.  152  Engravings  on  Wood.  3d  Edition, 
Revised  In  Preparation. 

FULLERTON.  Nursing  in  Abdominal  Surgery  and  Diseases 
of  Women,  ad  Edition.  70  Illustrations.  fi-5* 


SUBJECT  CATALOGUE. 


COMPENDS. 


From  The  Southern  Clinic. 

"  We  know  of  no  series  of  books  issued  by  any  house  that  so  fully 
meets  our  approval  as  these  ?  Quiz-CompendsT.  They  are  well  ar- 
ranged, full,  and  concise,  and  are  really  the  best  line  of  text-books  that 
could  be  found  for  either  student  or  practitioner." 


BLAKISTON'S  ?QUIZ-COMPENDS? 

The  Best  Series  of  Manuals  for  the  Use  of  Students. 
Price  of  each,  Cloth,  .80.         Interleaved,  for  taking  Notes,  $1.25. 

49"*  These  Compends  are  based  on  the  most  popular  text-books 
and  the  lectures  of  prominent  professors,  and  are  kept  constantly  re- 
vised, so  that  they  may  thoroughly  represent  the  present  state  of  the 
subjects  upon  which  they  treat. 

£&*'  The  authors  have  had  large  experience  as  Quiz-Masters  and 
attaches  of  colleges,  and  are  well  acquainted  with  the  wants  of  students. 

JK^  They  are  arranged  in  the  most  approved  form,  thorough  and 
concise,  containing  over  600  fine  illustrations,  inserted  wherever  they 
could  be  used  to  advantage. 

Jt&-  Can  be  used  by  students  ot  any  college. 

^~  They  contain  information  nowhere  else  collected  in  such  a 
condensed,  practical  shape.  Illustrated  Circular  free. 

No.  i.  POTTER.  HUMAN  ANATOMY.  Fifth  Revised  and 
Enlarged  Edition.  Including  Visceral  Anatomy.  Can  be  used 
with  either  Morris's  or  Gray's  Anatomy.  117  Illustrations  and  16 
Lithographic  Plates  of  Nerves  and  Arteries,  with  Explanatory 
Tables,  etc.  By  SAMUEL  O.  L.  POTTER,  M.D.,  Professor  of  the 
Practice  of  Medicine,  Cooper  Medical  College,  San  Francisco  ;  late 
A.  A.  Surgeon,  U.  S.  Army. 

No.  a.  HUGHES.  PRACTICE  OF  MEDICINE.  Parti.  Fifth 
Edition,  Enlarged  and  Improved  By  DANIEL  E.  HUGHES,  M.D  , 
Physician-in-Chief,  Philadelphia  Hospital,  late  Demonstrator  ot 
Clinical  Medicine,  Jefferson  Medical  College,  Phila. 

No.  3.  HUGHES.  PRACTICE  OF  MEDICINE.  Part  II. 
Fifth  Edition,  Revised  and  Improved.  Same  author  as  No.  2. 

No.  4.  BRUBAKER.  PHYSIOLOGY.  Eighth  Edition,  with 
new  Illustrations  and  a  table  of  Physiological  Constants.  Enlarged 
and  Revised.  By  A.  P.  BRUBAKER,  M.D.,  Professor  of  Physiology 
and  General  Pathology  in  the  Pennsylvania  College  of  Dental 
Surgery  ;  Demonstrator  of  Physiology,  Jefferson  Medical  College, 
Philadelphia 

No.  5.  LANDIS.  OBSTETRICS.  Fifth  Edition.  By  HENRY  G. 
LANDIS,  M.D.  Revised  and  Edited  by  WM.  H  WELLS,  M.D., 
Assistant  Demonstrator  of  Obstetrics,  Jefferson  Medical  College, 
Philadelphia.  Enlarged.  47  Illustrations. 

No.  6.  POTTER.  MATERIA  MEDICA,  THERAPEUTICS, 
AND  PRESCRIPTION  WRITING.  Sixth  Revised  Edition 
(U.  S.  P.  1890).  By  SAMUEL  O.  L.  POTTER,  M.D.,  Professor  of 
Practice,  Cooper  Medical  College,  San  Francisco  ;  late  A.  A.  Sur- 
teon,  U.  S.  Army. 


MEDICAL  BOOKS. 


PQUIZ-COMPENDS  ?—  Continued. 

No.  7.  WELLS.     GYNECOLOGY.     A   New  Book.     By  WM. 

H.  WELLS,  M.D.,  Assistant  Demonstrator  of  Obstetrics,  Jefferson 
College,  Philadelphia.  150  Illustrations. 

No.  8.  GOULD  AND  PYLE.  DISEASES  OF  THE  EYE 
AND  REFRACTION.  A  New  Book.  Including  Treatment 
and  Surgery,  and  a  Section  on  Local  Therapeutics.  By  GEORGE 
M.  GOULD,  M.D.,  and  W.  L.  PVLE,  M.D.  With  Formulae,  Glossary, 
Tables,  and  in  Illustrations,  several  of  which  are  Colored. 

No.  9.  HORWITZ.  SURGERY,  Minor  Surgery,  and  Bandag- 
ing. Fifth  Edition,  Enlarged  and  Improved.  By  ORVILLB 
HORWITZ,  B.S.,  M.D.,  Clinical  Professor  of  Genito-  Urinary  Surgery 
and  Venereal  Diseases  in  Jefferson  Medical  College  ;  Surgeon  to 
Philadelphia  Hospital,  etc.  With  98  Formulae  and  71  Illustrations. 

No.  10.  LEFFMANN.     MEDICAL    CHEMISTRY.      Fourth 

Edition.  Including  Urinalysis,  Animal  Chemistry,  Chemistry  of 
Milk,  Blood,  Tissues,  the  Secretions,  etc.  By  HENRY  LEPPMANN, 
M  D.,  Professor  of  Chemistry  in  Pennsylvania  College  of  Dental 
Surgery  and  in  the  Woman's  Medical  College,  Philadelphia. 

No.  ii.  STEWART.  PHARMACY.  Fifth  Edition.  Based  upon 
Prof.  Remington's  Text-Book  of  Pharmacy.  By  K.  E.  STEWART, 
M  D.,  PH.G.,  late  Quiz-Master  in  Pharmacy  and  Chemistry,  Phila- 
delphia College  of  Pharmacy  ;  Lecturer  at  Jefferson  Medical 
College.  Carefully  revised  in  accordance  with  the  new  U.  S.  P. 

No.  la.  BALLOU.  VETERINARY  ANATOMY  AND  PHY- 
SIOLOGY. Illustrated.  By  WM.  R.  BALLOU,  M.D.,  Professor 
of  Equine  Anatomy  at  New  York  College  of  Veterinary  Surgeons  ; 
Physician  to  Bellevue  Dispensary,  etc.  29  graphic  Illustrations. 

No.  13.  WARREN.  DENTAL  PATHOLOGY  AND  DEN- 
TAL MEDICINE.  Second  Edition,  Illustrated.  Containing 
a  Section  on  Emergencies.  By  GEO.  W.  WARREN,  D.D.S.,  Chief 
of  Clinical  Staff,  Pennsylvania  College  of  Dental  Surgery. 

No.  14.  HATFIELD.  DISEASES  OF  CHILDREN.  Second 
Edition.  Colored  Plate.  By  MARCUS  P.  HATFIELD,  Profes- 
sor of  Diseases  of  Children,  Chicago  Medical  College. 

No.  15.  HALL.  GENERAL  PATHOLOGY  AND  MORBID 
ANATOMY.  91  Illustrations.  By  H.  NEWBERRY  HALL,  PH.G., 

M.D.,  late  Professor  of  Pathology.'Chicago  Post-Graduate  Medi- 
cal School. 

No.  16.  DISEASES  OF  THE  SKIN.  By  JAY  T.  SCHAMBERG, 
M.D.,  Instructor  in  Skin  Diseases,  Philadelphia  Polyclinic.  Illus. 

Price,  each,  Cloth,  .80.  Interleaved,  for  taking  Notes,  $1.25. 

In  preparing,  revising,  and   improving   BLAKISTON'S    ?  Qmz-CoM- 
DS  ?  the  particular  wants  of  the  student  have  always  been  kept  in 


PEN 


^».  eful  attention  has  been  given  to  the  construction  of  each  sentence, 
and  while  the  books  will  be  found  to  contain  an  immense  amount  of 
knowledge  in  small  space,  they  will  likewise  be  found  easy  reading ; 
there  is  no  stilted  repetition  of  words ;  the  style  is  clear,  lucid,  and  dis- 
tinct. The  arrangement  of  subjects  is  systematic  and  thorough  ;  there 
is  a  reason  for  every  word.  They  contain  orer  600  illustrations 


Tyson's 
Practice  of 
Medicine.  lllustrated 


Just  Ready. 


A  Text-Book  of  the  Practice  of  Medi- 
cine. With  Special  Reference  to  Diagnosis 
and  Treatment.  By  JAMES  TYSON,  M.  D., 
Professor  of  Clinical  Medicine  in  the  Univer- 
sity of  Pennsylvania;  Physician  to  the  Hos- 
pital of  the  University  and  to  the  Philadelphia 
Hospital ;  Fellow  of  the  College  of  Physicians 
of  Philadelphia,  etc. 


With  Many  Useful  Illustrations. 

Octavo.      1180  Pages. 
Cloth,  $5.50;  Sheep,  $6.50;  Half  Russia,  $7.50. 


Extracts  from  a  Review  in  the  American  Journal  of 
Medical  Sciences,  March,  1897: 

"  Externally  it  is  the  largest  and  handsomest  single  volume 
on  the  practice  of  medicine." 

"  Clinical  features  are  usually  described  in  a  masterly  way." 

"The  directions  (for  treatment)  are  full  and  clear,  and  as 
a  rule,  eminently  judicious  and  conservative." 

"Dr.  Tyson's  style  is  already  so  well  known  in  medical 
literature  that  it  is  only  necessary  to  say  the  present  work  is 
one  of  the  best  examples  " 

"We  welcome  Dr.  Tyson's  Practice  as  a  most  valuable 
addition  to  medical  literature." 

Descriptive  circular  and  sample  pages  upon  application. 


This  book  is  DUE  on  the  last  date  stamped  below 


DEC  . 
EC  \\ 


L  LIB. 


. 

NOV261969 


Form  L-9-15m-7,'32 


Southern  Branch 
of  the 

University  of  California 

Los  Angeles 

Form  L   1 


n-a  LSCHOUL 

US  Sv  ->OAf. 


